- cctalk - classiccmp.org

ID'ing a core module: Any Univac 1108/6 processors still existent?

by Brent Hilpert

I was asked to examine a large core module, it has a UNIVAC label and part no, manufactured in 1971 but probably a little older in design. No providence known. I suspect it is from an 1108 or perhaps an 1106, based on the reasoning presented in the web link below. I’m a little curious for a firmer confirmation though. 1108/6 documentation on bitsavers has been very useful, but what’s there doesn’t go deep enough into the hardware to provide a hard confirmation. Is there even an 1108 or 6 still in existence? The module, and what I’ve figured out: http://madrona.ca/e/coreUnivac/index.html <http://madrona.ca/e/coreUnivac/index.html>

1 hour, 40 minutes

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TECHNOLOGY SWAP MEET & Fundraiser - Wall, NJ - May 30, 8AM to 2PM

by Jeffrey Brace

TECHNOLOGY SWAP MEET & Fundraiser = May 30, 2026, 8AM to 2PM, Wall, NJ - 6th St and Monmouth Boulevard https://vcfed.org/vcf-swap-meet/ Vendor Setup at 7AM Vendor Registration: https://docs.google.com/forms/d/e/1FAIpQLSdZcnVFT2lfJJuYwwJSwclxfyvZFBd1kp1…

23 hours, 27 minutes

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Project Release Announcement - Vintage UNIX (and others) Online Manuals

by r.stricklin

I've been working on this project for ages. It is not complete. It may never be complete. It is, however, finally in a state that I consider to be eminently usable. A "beta" or "soft opening" - there are absolutely some visibly unfinished areas. But, it can absolutely be used while I continue improving the typesetter and the indexer, polishing the presentation, and adding manuals for new systems. http://www.typewritten.org/Manual/ Some folks were given access to previous development versions and asked not to share the URLs. If you were one of them, please transition to this URL instead; this one can be considered fully public. ok bear. ps. this announcement was also sent to the VCFED forum and the TUHS mailing list

1 day, 6 hours

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Emulex UD33 + Fujitsu M2284K sectoring

by Jacob Ritorto

Hi all, I have this UD33 controller that works perfectly with another newer SMD disk (CDC 9720), but when I try it against my beautiful old Fuji 160 (M2284K), It gets through format okay but has intermittent errors on verify / reliability test. If I reduce the number of cylinders / heads, I can get it to pass, but not every time. I have a good thick ground and same cables that worked perfectly with the other disk, hoping that's enough of a sanity check on those. I have the UD33 configured thusly: type: 1 units: 1 sectors per track: 32 physical heads: 10 physical cylinders: 823 spare sectors per track: 1 spare cylinders: 2 configuration bits: 6 LOWER RPS: 3 UPPER RPS: 7 split into one drive with 1 head and the other with 9 heads to speed things along :) GAP 0: 259 GAP 1: 4112 GAP 2: 780 Spiral offset: 1 The drive's switches are set for soft sectoring and tag 4/5 enabled. I had tried hard sector setting on the drive with 32 sectors / 640 bytes. It's SO CLOSE to working I can taste it :). I have another Fuji 160 that is doing basically the identical same misbehaviour. And as usual, I am just not quite understanding the final clincher piece. Anyone know of better settings I should be using and most importantly Why? thx jake P.S. I was hoping that somewhere someone would have written down what controller settings work with the UD33 or QD32, etc, but no luck finding them. You'd think despite the 3 or so years gap in the disk vs controller that this would've been officially supported at some moment in the universe, no? I just wish I knew how to calculate it properly myself!

2 days, 4 hours

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Rainbow 100 and Univation Hard Disk

by Robert Armstrong

I have a Rainbow 100A with the Univation hard disk. Works (wow!), but the Univation HDD controller was not DEC compatible and you have to boot from a floppy to get the disk drivers loaded. And of course, the 100A ROMs didn't support any kind of hard disk, DEC or otherwise. Did anybody ever make an updated ROM image for the 100A that supported booting from the Univation directly? I think the 100A used 2716 EPROMs, and it'd be easy enough to burn some new ones. And is there any surviving documentation for the Univation? Bitsavers seems to have nothing. Thanks!

3 days, 17 hours

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xterminal

by cp

hi I have a tektronix xp217, with Tekxpress v7. Are you interested? let me know

3 days, 21 hours

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Did anyone here work on Burroughs A Series/Large Systems MCP back in the day?

by Alan Perry

Hi all, I worked on system software at Burroughs in the late 80s and a couple weeks ago gave a talk about Burroughs history in computers and the Large Systems/A Series/B5000 and B6500 architecture at VCF PNW. There was enough interest that I am putting together another talk or two. One of the topics is Large Systems MCP and I am looking for other people who worked with it to give their own perspective and confirm things I am trying to remember from 40 years ago. BTW, if you haven’t seen it, the trove of Burroughs documents in the bitsavers Burroughs collection on the Internet Archives is amazing. Unfortunately I still can’t find any documentation for most of the stuff that I worked on. I should have kept copies of those manuals when I left. alan

6 days, 1 hour

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Odd grounding issue with 19" Sun LCD

by Steve Lewis

Apologies for spamming this with a very specific hardware issue - but I felt this was so unusual, that it was worth sharing the kind-of solution. I have an old 386 running Solaris, works fine. I swapped the VGA monitor it, didn't think much of it. VGA is VGA right? (except old Compaq 286SLT have one of the VGA pins removed, but that's another story) The replacement monitor (19" Sun from c. 2001) worked fine. Booted system, logged in. But - I Couldn't ping. No networking. Checked the router. Check switch, all green lights. TV streaming still working. No one else in the house screaming about no internet. Hmm... But I couldn't ping out of that 386, nor FTP back into it, like I had been. I consulted GPT on its thoughts. I swapped NIC cables, VGA cables, long cables, short cables, moved the power brick of the 19" Dell. All same result. Finally, GPT made this comment, that I'll summarize like this: "If your NIC isn't working, try turning off your monitor." I figured another dumb AI hallucination. But holy smokes, that actually worked! It was a pure 1:1 correlation - whenever I turned that 19" Sun monitor off, I could ping out of the box and ftp into it. As soon as I powered it back on, all the network traffic stopped. It no fancy LCD - no speakers, no USB, just a typical VGA/DVI connector heavy LCD with a Sun Micro logo stamped on it. So the specific test was this: prep a ping command, like "ping 192.168.1.1" turn the monitor off, press ENTER. Wait 2 seconds, power the monitor back on. And yea, consistently, that worked. But when trying to ping while the monitor was left on, I couldn't ping from the NIC in this 386. GPT's only suggestion was some sort of grounding interference by this particular 19" Sun monitor, and some blah-blah about how old 386's are more impacted about EMI. Just curious what other think on this - any particular known issue about 2001-ish period Sun 19 flat-panel LCDs? This one uses a 19V DC power brick (and I tried using different outlets). I never would have considered trying to solve the NIC issue by powering off the monitor. So I have to put back on the widescreen for now - which everything works fine with that. So not a real solution, but I gotta admit that GPT did help uncover what was causing the issue. Cheers, Steve

1 week

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MIMIC microcomputer information

by wrcooke＠wrcooke.net

I ran across an ad in the March 1979 Popular Electronics. It is for a small computer board called "MIMIC" from Real Time Intelligence Corporation of Rochester, NY. From the picture and small amount of information in the ad I am guessing it is a minimal 6802 processor system. I am interested in knowing more about it, but so far my searches have turned up nothing on the computer or the company. Does anyone know anything about it? Links to info? The magazine can be found here https://www.worldradiohistory.com/Popular-Electronics-Guide.htm and the ad is on page 6 (8 of the PDF.) Thanks, Will You just can't beat the person who never gives up. Babe Ruth

1 week, 2 days

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VCF West 2026 Call for speakers! Aug. 1 & 2, Mountain View, CA

by Jeffrey Brace

VCF WEST 2026 CALL FOR SPEAKERS! We have a new exhibit registration system: https://em.vcfed.org/events/vcf-west-2026/speaker-signup DATES: Aug 1st and 2nd at the Computer History Museum in Mountain View, CA. INFO:https://vcfed.org/vcf-west

1 week, 2 days

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FTGH Old Issues of IEEE SigSoft Software Engineering Notes

by Rob Jarratt

I have a ton of these covering the period from around 2000-2005. I may have more. Are they of interest to anyone? They are in the UK. Would prefer local collection, I could post them in the UK if needed. They are going to be heavy, but if anyone *really* wants them then I might be prepared to ship them internationally. Obviously shipping will be for the recipient to pay, but the journals are free. Thanks Rob

1 week, 3 days

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Charles Simonyi on his flying experience with Howard

by Paul McJones

This is a very poor machine transcription of a Zoom conversation I had with Charles about 5 years ago. I went flying with him once a month. 00:15:04 Charles Simonyi Yeah the yeah this uh this kind of third hand plane and then flying with him and. 00:15:15 Charles Simonyi We were flying at night and we had a complete electrical failure. 00:15:21 Paul McJones Oh, really. 00:15:22 Charles Simonyi Yeah, in the San Jose airspace. 00:15:27 Charles Simonyi And dum dum. 00:15:31 Charles Simonyi There are actual procedures to come to. 00:15:37 Charles Simonyi Do. 00:15:40 Charles Simonyi You approach an airport with radio failure. 00:15:43 Charles Simonyi He was supposed to fly by the You know lookout. 00:15:47 Charles Simonyi Of course it was. 00:15:48 Charles Simonyi It was completely beautiful weather, you know, zillion visibility and and you were supposed to fly by the. 00:15:57 Charles Simonyi Uhm, he knew all the procedure. 00:16:00 Charles Simonyi We fly by the the control tower and then they guide you down with this thing called the light gun. 00:16:07 Charles Simonyi Which is a colored oh colored thing that actually you can see even in the movies. 00:16:13 Charles Simonyi You can see it kind of hanging from the from the ceiling. 00:16:16 Charles Simonyi There's this big flashlights, you know that you you can direct at planes and and and the weird thing is that that. 00:16:27 Charles Simonyi I was learning to fly at the time, so I'm doing a little bit of knowledge and and the when you clear to land, it's a it's steady green. 00:16:38 Charles Simonyi And flashing green means standby. 00:16:40 Charles Simonyi OK, wait for the client and and we saw this. 00:16:45 Charles Simonyi I saw flashing green. 00:16:47 Charles Simonyi And I said, wait, wait, it's we are not clear. 00:16:50 Charles Simonyi Yeah. 00:16:51 Charles Simonyi And and how it said no, no, no. 00:16:53 Charles Simonyi That's a steady light, except that they are not hitting us, right? 00:16:58 Charles Simonyi Oh Oh yeah, yeah. 00:16:58 Charles Simonyi Oh yeah. 00:16:58 Charles Simonyi 00:16:59 Charles Simonyi So I've just realized and and he said just look very close to the source and you can see a little bit of of the beam and see that it's steady. 00:17:10 Paul McJones OK. 00:17:10 Paul McJones OK. 00:17:11 Charles Simonyi And and I realized. 00:17:13 Charles Simonyi I mean, I still remember how. 00:17:15 Charles Simonyi You know, and then you would have to see this in a simulator or something. 00:17:19 Charles Simonyi Otherwise you know if I had been alone, I would have never landed because they they can't take you straight. 00:17:26 Paul McJones Yeah, yeah. 00:17:26 Charles Simonyi And I was thinking about this silly, silly distinction. 00:17:31 Charles Simonyi Because, operationally, it's it's very difficult to tell the difference, But anyway.

1 week, 4 days

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HP9100

by hupfadekroua

Hi all, today it happened to me I got a lot of stuff - spares for my HP9100, which do have the status of almost unobtanium: - three cathode ray tubes, just tested and working - two complete board sets - several core memory boards Andreas

1 week, 4 days

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VCF West 2026 Call for exhibitors: Aug 1 & 2, Mountain View, CA

by Jeffrey Brace

VCF WEST 2026 CALL FOR EXHIBITS! We have a new exhibit registration system: https://em.vcfed.org/events/vcf-west-2026/exhibitor-signup DATES: Aug 1st and 2nd at the Computer History Museum in Mountain View, CA. INFO: https://vcfed.org/vcf-west Jeff Brace

1 week, 4 days

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VCF Tech Swap Meet. Sat. May 30. Wall, NJ.

by Jeffrey Brace

VCF Tech Swap Meet. Sat. May 30. Wall, NJ. Vintage Computers, Electronics, Radios, TVs, Amateur Radio, Tech VENDOR REGISTRATION: https://forms.gle/v9U9ZPVFDTQu56hF9 INFO: https://vcfed.org/vcf-swap-meet/

2 weeks, 1 day

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Apollo DSP80A/90 documentation?

by Kurt Nowak

Just a shot in the dark, but does anyone here happen to have a collection of Apollo documentation, specifically for the DSP80A/90? According to the Apollo documentation index they would be: Operating the DSP80A/DSP90 - number 004957 Unpacking and installing the DSP80A/DSP90 - number 004958 and Servicing the DSP80A/DSP90 - number 005806. Unsurprisingly, between my collection and Bitsavers, I cant seem to find anything on line anywhere. I'd be pleasantly surprised if i wasn't the owner of the only remaining DSP90. -Kurt

2 weeks, 2 days

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Re: Looking for MULTICS "screenshots"

by Craig Ruff

You can also run Multics in a simulator: https://dps8m.gitlab.io/dps8m It's been a while since I've been actively involved in that project, but it ran nicely.

2 weeks, 2 days

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Looking for MULTICS "screenshots"

by Steve Lewis

I realize MULTICS is from teletype era - so probably no old photographs showing MULTICS output in that form. But looks like MULTICS was actually in use for a couple decades, maybe some photo of a CRT with aspects of MULTICS presentable? Mostly trying to verify what the "list" command output looked like. But it should have some way to list processes also. -Steve

2 weeks, 2 days

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pulling data from IBM 3480 tapes - anyone interested in $$

by Bill Degnan

I have an opportunity to read some 3480 and related IBM format tapes, looking for someone in the Phila area who has the hardware to archive/retrieve the data from this format. This would be a service for which you would get paid. Contact me privately through kennettclassic.com/contact.cfm Thanks BIll

2 weeks, 3 days

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Massbus emulation

by Jim Bender

Does anybody here still use Massbus? Or have a Massbus system you’d like to run, but the idea of dealing with washing-machine disk drives is a bit less appealing these days? In what may classified as a momentary lapse of reason, I have taken up the old Living Computer Museum Massbus emulator project and am in the process of resurrecting / modernizing it. Current progress photo here: http://www.dmv.net/mbe/mbe1.jpg Why, you ask? "Has he gone insane?" are you thinking? I have three PDP-11/70s that I would like to get running again. Sure, I could cheat and hang a UNIBUS SCSI controller with a ZuluSCSI disk simulator, but where is the fun in that? Also, the 11/70 was designed and optimized around Massbus for primary storage, so it seems only fitting to use it that way. The original LCM emulator used a PC with a Mesa 5I22 FPGA card as the Massbus interface. The FPGA implemented the drive-side bus logic, while the PC software emulated the backing disk or tape image. A driver/receiver (“D/R”) board sat in the middle to translate the Massbus differential signals into logic levels suitable for the FPGA. It worked... Since Mesa 5I22 cards are now pretty much unobtainium, I went looking for a cleaner and more modern approach. The result is a redesigned D/R board that accepts a Terasic DE10-Nano directly. The DE10-Nano is a small Linux SBC with a Cyclone V FPGA onboard, so it can host the emulator software itself while the FPGA handles the Massbus interface duties that were previously done by the Xilinx FPGA on the Mesa card. Same general architecture, but much tidier. There is still work to do, but it is coming along nicely. The board in the photo is not yet fully populated, since I am doing incremental testing before committing the rest of the parts. As I have gone down this rabbit hole, naturally a few questions in the “why did they do THAT??” category have come up... paging @Rich Alderson ... If anyone here is still actively using Massbus, has experience with the original LCM project, or just has relevant war stories, comments, warnings, or encouragement, I would be glad to hear them. Cheers! Jim

2 weeks, 5 days

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VCF West 2026 Registration is open!

by Jeffrey Brace

VCF West 2026 will be held on August 1st and 2nd at the Computer History Museum in Mountain View, CA. We have opened registration for exhibits, vendors, speakers, and volunteers. Please visit our event application at https://em.vcfed.org/events/vcf-west-2026 to register. Also, please note that this software is new, so there may be a bug or two. Please report any issues, or send any questions or comments to vcfwest(a)vcfed.org. Thank you! Jeff Brace VCF West co-showrunner

3 weeks, 4 days

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Re: Why do we do these things? (was: Massbus emulation)

by Kevin McQuiggin

It is nice to get back to these old programs. A few years ago I fixed a bug in an undergrad chess “knight’s tour” program I wrote when I was about 18. It was written in PL/I. Last edit: 1978; I happily added “bug fix, 2016”. I knew of the bug, just never got around to fixing it. I added some printout improvements too. I had the Hercules S/360 emulator running. MVS 3.7j I recall. Memory lane trip for sure. JCL? Had to find my “green book”! Kevin Sent from my iPhone > On Apr 24, 2026, at 12:34, Paul Koning via cctalk <cctalk(a)classiccmp.org> wrote: > > > >> On Apr 24, 2026, at 3:26 PM, Brian L. Stuart via cctalk <cctalk(a)classiccmp.org> wrote: >> >> Very cool. A while back, I resurrected one of my senior >> projects from 1984, a little Forth-based OS for the PDP-11. >> It was originally implemented on an 11/34 with an RK05, >> but now I've got it on a little LSI-11 in a BA11-VA box >> with a little 6809 board I build and wrote a TU58 emulator >> for. > > I recently started playing a lot more with Forth. The main reason is that I ran into a very nice extended Forth system for the Raspberry Pico, which makes for a much nicer development environment than the vendor-supplied C API. It's a bare metal system, implemented mostly in Forth with the low level bits in assembly language. No C or C++ anywhere. > > https://github.com/tabemann/zeptoforth > > It does networking, too. I've been using it to develop a nice NTP server (and disciplined oscillator), very nice and small. > > paul >

3 weeks, 6 days

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Re: Massbus emulation

by Mark Kahrs

At LSSM, we have 2 KS10s and 1 11/70. We have one of the LCM emulators connected to a KS10, but alas, both KS10 power supplies are now deceased, so we are working on replacements. The emulator seems to work fine, for as much as we've used it. Of course, the Massbus connectors are made of unobtanium and must be scrounged from elsewhere.

4 weeks

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VCF East 2026 Post Event Surveys

by Jeffrey Brace

VCF East was quite successful in many ways. Please take a few minutes by answering this anonymous survey: https://www.surveymonkey.com/r/97RMZSJ

4 weeks, 1 day

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Ken and Roberta Williams at VCF East (virtually), Wall, NJ April 18, 11AM

by Jeffrey Brace

Ken and Roberta Williams of Sierra Online will appear virtually at VCF East 2026, Saturday, April 18 at 11AM. After a 10 minute introduction, they will take questions from the in-person audience. For tickets to VCF East: https://events.humanitix.com/vcfeast2026?c=cctalk For info: https://whova.com/web/GHMfP%40%40JlCnOF3xlEWLmBBm1POMpM3REEcBH%40BfF1SA%3D/ Take care! Jeff Brace VCF East Showrunner

1 month, 1 week

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Re: Kodak Diconix 150plus - looking for info

by Sunil Vadgama

Hello Sir, I have this printer with Parallel Centronics connection. How do I print something using modern pc? Thanks for information on power connection, great help. Thanks Sunil

1 month, 1 week

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Bill Mensch will talk at VCF East on April 18 at 5PM in Wall, NJ.

by Jeffrey Brace

Co-inventor of the MOS 6502 microprocessor. He will talk about what he did after leaving MOS Technology Corp. TICKETS: https://events.humanitix.com/vcfeast2026?c=cctalk INFO: https://whova.com/web/GHMfP%40%40JlCnOF3xlEWLmBBm1POMpM3REEcBH%40BfF1SA%3D/

1 month, 2 weeks

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M9301-YA.mac

by Roman Petrov

Dear Noel, Thank you very much for making the M9301-YA.mac file publicly available (https://www.classiccmp.org/pipermail/cctalk/2015-April/006241.html), but I can't download it... When I try to download it, I get the message: "You don't have permission to access /~jnc/tech/pdp11/M9301-YA.mac on this server." Could you please email me the M9301-YA.mac file archive? With best wishes Roman

1 month, 2 weeks

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Lee Felsenstein talk at VCF East on April 19 at 3PM in Wall, NJ

by Jeffrey Brace

Meet Lee Felsenstein will talk at VCF East on April 19 at 3PM in Wall, NJ. A central figure of the legendary Homebrew Computer Club. He is best known for The Osborne 1, The Sol-20, Community Memory. Don't miss the chance to hear from a pioneer who didn't just build the tools, but changed the rules. TICKETS: https://events.humanitix.com/vcfeast2026?c=cctalk INFO: https://whova.com/web/GHMfP%40%40JlCnOF3xlEWLmBBm1POMpM3REEcBH%40BfF1SA%3D/ Take care! Jeff Brace VCF East Showrunner

1 month, 2 weeks

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Tracy Kidder, Author of ‘The Soul of a New Machine,’ Dies at 80

by Christian Liendo

Tracy Kidder, Author of ‘The Soul of a New Machine,’ Dies at 80 A Pulitzer Prize-winning narrative journalist, he wrote deeply reported books that often focused on heroic goodness in people. https://www.nytimes.com/2026/03/25/books/tracy-kidder-dead.html?unlocked_ar…

1 month, 2 weeks

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George Goble passed away

by Christian Liendo

George Goble passed away https://www.legacy.com/us/obituaries/wlfi/name/george-goble-obituary?id=611… From Wikipedia: https://en.wikipedia.org/wiki/George_H._Goble George Harry Goble (December 11, 1952 – March 18, 2026) was an American scientist and academic, who was a staff member at the Purdue University Engineering Computer Network and a 1996 Ig Nobel Prize winner. Goble was commonly known as ghg, since he used that as a login id and signature in digital communications from the 1970s. He received his BS in Electrical Engineering at Purdue University. In 1981, he wired together the backplanes of two DEC VAX-11/780 systems and made the first multi-CPU Unix computer, preceding DEC's dual processor VAX-11/782.[1] The operating system was based on the 4.1 BSD kernel,[1]: 293 and the modifications thus eventually made it into the 4.3 BSD Unix release.[citation needed] At the beginning of the 4.3 BSD user manuals, Bill Joy wrote a special note of thanks to GHG for being courageous enough to put the multi-CPU kernel into a production environment before anyone else did.[2] (However, the frequent crashes for a while inspired the writing of many humorous text files by the Purdue University Electrical Engineering student body, such as "The VAX had a Blowout", to be sung to the tune of "London Bridge is Falling Down".) The development of the Dual-CPU Unix system was the subject of Goble's Master's thesis. Around this time, Goble, along with Bill Croft, also developed a networking protocol for Unix, referred to as pnet, which was used at Purdue at the time before being displaced by TCP/IP. Pnet allowed remote logins, and remote execution of commands, among other capabilities.[3] In the late 1980s, Goble started experimenting with refrigerants, due to increased danger and lower thermodynamic efficiency of the recently introduced R-134a compared to the older R-12 which was being phased out due to concerns about damage to the ozone layer, and the incompatibility of R-134a with the lubricating oil and other materials used in systems built for R-12. In 1987, he converted the beverage refrigerators in the Eta Kappa Nu lounge in the basement of the Purdue Electrical Engineering building to using a refrigerant of his own devising. This refrigerant is now recognized as R-406A by ASHRAE and is available commercially under the trade name AutoFrost. He later developed another refrigerant which is compatible with R134A lubricants, but which is superior in thermodynamic efficiency and lower system internal pressures called GHG-X8. In 1996, Goble was awarded the Ig Nobel Prize in Chemistry, for preparing a barbecue for cooking in less than 5 seconds by the use of a smoldering cigarette, charcoal and LOX (liquid oxygen).[4] This act attracted the attention of the West Lafayette, Indiana fire department, which warned him to never let them catch him in the possession of LOX near a barbecue fire ever again. Goble was also noted for driving a vehicle with the Indiana license plate UNIX, and also GHG-1 https://engineering.purdue.edu/ECE/Alums/OECE/2022/George-Goble

1 month, 2 weeks

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Compaq 9.1GB Ultra3 SCSI disks + Hot Plug Drive Trays

by Johan Helsingius

Anyone need Compaq hot plug SCSI drives and/or drive trays (part number 386536-001)? I have 16 of them spare. Julf

1 month, 3 weeks

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Apple

by Murray McCullough

According to legend, so it has been proven to be a fact, Apple was created 50 years ago today. The classic computing world is one reason we as members can look back and witness the contribution Apple has played. Whether this is a mixture of delight or sadness doesn't take away the contribution Jobs and Wozniak played in my and others interest in keeping classic computing alive. Happy computing all. Murray

1 month, 3 weeks

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QIC tape replacement bands

by Alan Perry

Hi all, I am looking for advice on some problems that I am observing trying to read QIC tapes using an Archive Viper. If you are unfamiliar with QIC tapes, tape transport is done through a single roller that moves a plastic band in tension with the outside of a portion of the tape on the reels. Over time, the band will break. A long time ago, I bought a bunch of the green plastibands to use as replacement bands. Later I bought a bunch of the clear ones. I was able to image some tapes with the plastiband replacement but not all (but rewind and retension works almost every time). Until today, I don't think I ever tried the clear ones after I bought a bag. I am preparing for a VCF and need the contents off of some of the tapes that I have, so I got out the driver and tapes. However, I have been unable to read anything from the them. The tape will jam up. It seems like what is happening is that plastiband is not providing enough tension to move the tape when reading. The tape loses tension and I see it gather instead of moving along. Sometimes the tape feels stuck to the posts that turn the tape to be parallel with the heads. I also tried a clear band for the first time and the tension with that seems too tight. What am I doing wrong? alan

1 month, 3 weeks

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Maxtor XT1140 Drives

by hupfadekroua

Hi all, are there any experiences or hints in reviving and repairing Maxtor XT1140 and 2190 drives. I do have a pile of TI-Expore Bricks. The disc drives do have issues like: - not spinning up - spinning up but not recalibrating - .. Andreas

1 month, 3 weeks

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Re: QIC tape replacement bands

by Jonathan Haddox

I was able to get some newer QIC-150 tapes by 3M and harvested the belts out of them. Dropping the belt into boiling water for 20 seconds revived their tension strength. Ultimately what brought me success though was replacing the posts in the tape cartridge with roller bearings that I purchased at a hobby store. The bearings were meant for wheels on an R/C car. Even with the sticky stuff on the tape, they did not bind up, it required a lot of cleaning of the R/W head though during data restore.

1 month, 3 weeks

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Re: Sun-1 netboot debugging

by Craig Ruff

I seem to recall that Sun 1 era systems used BOOTP for network booting. https://www.rfc-editor.org/rfc/rfc951

1 month, 3 weeks

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Sun-1 netboot debugging

by Mark Kahrs

We're trying to netboot a Sun-1. Initially, the machine issues the following packets (over and over...): 17:23:16.834126 In 00:00:00:00:00:00 (oui Ethernet) ethertype IPv4 (0x0800), length 90: localhost.52483 > localhost.domain: 9273+ PTR? 255.255.255.255.in-addr.arpa. (46) 17:23:16.834158 In 00:00:00:00:00:00 (oui Ethernet) ethertype IPv4 (0x0800), length 118: localhost > localhost: ICMP localhost udp port domain unreachable, length 82 After a short while (10 seconds?), it gives up (because the ndd server doesn't recognize it), it times out and then generates the following packet: 17:23:26.333093 B 02:60:8c:03:40:50 (oui Unknown) ethertype IPv4 (0x0800), length 64: 0.3.64.80 > 0.0.0.0: nd 28 Where, of course, the ...:40:50 is the MAC address in the source address. Does this ring a bell with anyone? n.b. This seems to pre-date RARP, so any insight would be valuable. T

1 month, 3 weeks

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Re: ISO: Manual for Fujitsu M2372K SMD drive

by Jacob Ritorto

I recall I trusted the Stanton geometry specs and had success with my 2372. Was working great until power supply blew. I used a QD33 and an SC41 just fine so I think you’re on course to success. Jake > On Oct 13, 2015, at 02:54, Josh Dersch <derschjo(a)gmail.com> wrote: > > Subject line covers it; the M2372K manual isn't on Bitsavers (the 2382K is, but it's significantly different) and all I've found is this covering the basics, and I'm not 100% sure it's correct: > > http://stason.org/TULARC/pc/hard-drives-hdd/fujitsu/M2372K-824MB-8-0-FH-HSM… > > Anyone have this manual? Can you confirm that the settings listed on stason.org are valid? I'm trying to get this drive to format using an Emulex UD33 (UNIBUS SMD) controller, and I'm not having much luck. (I'm also not certain that the 2372K isn't too new for the controller; another place a manual would be of immense help.) > > Thanks, > Josh >

1 month, 3 weeks

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Looking to ID a UNIVAC(?) 2x18 pin backplane Controller

by Bill Degnan

https://www.vintagecomputer.net/univac/UNIVAC-controller_front.png https://www.vintagecomputer.net/univac/UNIVAC-controller_rear.png Any ideas? Is this a late UNIVAC 1000 or early 9000 controller? OR could this be from a totally different manufacturer (Burroughs?) This controller would fit into a2x18-pin backplane. I don't think it's IBM. Bill

1 month, 3 weeks

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VM/370 notes

by Steve Lewis

Hey all, I was trying to track down some kind of image/photo of "what IBM VM/370 looks like" (the operating system) I tried looking also in the IBM manuals - I'm just not finding much. Some kind of image of what maybe a remote login looked like, a task process list, or maybe basic file/folder management commands, or how an editor or programming worked on that system. There is a bit of media with a VM/370 emulator, but I wasn't sure how accurately representative it was of a kind of "look and feel" of that OS. What I'd need is maybe photographs of teletype printouts? This was still early 1970s. Which is understandable not much of that was probably kept around. Thanks, just digging around - like wasn't sure if VM/370 was still six-character filename limited like earlier 60s era OS's, or whatever characteristics it had in operating it. -Steve

1 month, 3 weeks

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Reminder: Glen Ellyn CCC meeting - Tomorrow

by Mike Katz

*Just a reminder* The next Glen Ellyn CCC chat and repair meeting will be held on March 28th, 2026. Anytime after 2PM until we all get to tired to solder and talk. We will order Pizza around 5:30pm. As usual Beer and Pop will be provided. I look forward to seeing you all there. 385 Saint Charles Rd Glen Ellyn, IL 60137 +1 (773) 414-1044 (Cell)

1 month, 3 weeks

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Re: IBM MPX OS info c. 1970

by brian＠quarterbyte.com

The 1800 used the 1130's instruction set but from what I heard the CPU was faster. (Integer multiply and divide in particular). And it had some other differences, e.g. index registers were real registers, not the first three locations of core. Also it had a couple more instructions, and the ability to make sections of core readonly once initialized -- I believe this was done with toggle switches rather than under software control. It's been a while. From what I wrote on ibm1130.org/today, apparently at one time I believed Mike Ross and Bob Rosenbloom have 1800's I have never found a copy of MPX either as a distribution card set or disk image. Would LOVE to have it so we can try it out on the ibm1130 simulator in simh Brian

1 month, 3 weeks

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IBM MPX OS info c. 1970

by Steve Lewis

Hey all, I came across an OS called MPX for the IBM 1800 system. bitsavers has some documentation, but again I was hoping to get some sense (or photo) of what it "looked like" - process control list, disk/memory resource, or how one might interact or "run" FORTRAN on it. My understanding is the 1800 was basically an upright (fridge-style) version of the 1130? MPX is described as supporting both real-time and background processing. A main use case seems to be in factory automation (power plants, oil refineries, steel mills). Per this article, it looks like there was an effort to make a PC (x86) port of this MPX around 1989. https://dl.acm.org/doi/pdf/10.1145/65294.71219 (to me, making it a comtemporary to MINIX) Searching for IBM MPX info is confused since it looks like CDC had an MPX OS in the 1980s, and Microsoft more recently had some components called MPX (along with Intel once upon a time having MPX instructions). So it's a fairly overloaded term. Around the year 2000, there was an interview with Ray Gwinn (developer of high performance SIO drivers for OS/2) - in there, he describes using MPX on an 1800, as early as 1968. bitsavers main MPX archive doc is a 5th adition from 1970. Not urgent, was just a curiosity. I didn't see MPX mentioned in this epic IBM OS discussion: https://www.youtube.com/watch?v=ip0cQiQjd18 Maybe IBM MPX got overshadowed by the RSX-11 systems - but there are claim that IBM 1800's being in use as recently as 2010. -Steve

1 month, 3 weeks

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Need Heathkit H8 floppy data recovered

by Steven Stengel

Hello, Is there anyone here who has a working H8 or maybe H89 who can recover data from floppies? Thanks- Steve.

1 month, 3 weeks

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[OT] Tandy Assembly

by me＠scifidan.com

Tandy Assembly is Oct 2-4. Anyone planning to attend this year? I am going to get a hall pass from the old battleaxe. The airline prices are really good right now, for me at least. I am going to be a sponsor. Daniel sysop | Air & Wave BBS finger | calcmandan(a)bbs.erb.pw

2 months

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VCF East - April 17-19 - Wall, NJ - Tickets

by Jeffrey Brace

Vintage Computer Festival East 2026 April 17-19 InfoAge Science & History Center in Wall, NJ Tickets: https://events.humanitix.com/vcfeast2026?c=cctalk Discount Ticket Code: VCFEAST2026 Event Information: https://whova.com/web/d5dQ0Jxz4kVT1adFqNXwtZwcEf9ga1Zmqu4NwOb0oV0=/ Jeff Brace VCF East Showrunner

2 months

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Re: Seeking information on the CSTS Timesharing service

by Greg Ward

I worked on CSTS for about 25 years... starting in 1970

2 months

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Reminded: Glen Ellyn CCC meeting - March 28th

by Mike Katz

*Just a reminder* The next Glen Ellyn CCC chat and repair meeting will be held on March 28th, 2026. Anytime after 2PM until we all get to tired to solder and talk. We will order Pizza around 5:30pm. As usual Beer and Pop will be provided. I look forward to seeing you all there. 385 Saint Charles Rd Glen Ellyn, IL 60137 +1 (773) 414-1044 (Cell)

2 months

1
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Reminded: Glen Ellyn CCC meeting - March 28th

by Mike Katz

*Just a reminder* The next Glen Ellyn CCC chat and repair meeting will be held on March 28th, 2026. Anytime after 2PM until we all get to tired to solder and talk. We will order Pizza around 5:30pm. As usual Beer and Pop will be provided. I look forward to seeing you all there. 385 Saint Charles Rd Glen Ellyn, IL 60137 +1 (773) 414-1044 (Cell)

2 months

1
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Need to fix networking on a dos computer that runs a cnc machine

by Devin D'Amico

Hello all, I am at a bit of a loss. Looking to repair a dos computer that runs a big cnc machine. I need to load some kind of packet driver, so that the pc tcp software from the company "ftp software" can be loaded. Another supporting machine passes data to this machine to drive the machine. Attached are some screenshots. Original card was a pci etherexpress 100. The packet driver used is in the screenshots attached. I no longer have a intel card, is there a way to just drop in any old pci card and make it work with the tcp ip software? I am trying to better understand, as i have not done much work with packet drivers. I will post back with some more info. Any help much appriciated. --Devin D.

2 months, 1 week

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HOTEL BLOCKS EXPIRING Mar. 16 for VCF East 2026 in Wall, NJ

by Jeffrey Brace

HOTEL BLOCKS EXPIRING Mar. 16 for VCF East 2026. VCF East takes place at InfoAge Science and History Museums in Wall, NJ, April 17-19. Hotel blocks: https://vcfed.org/vcf-east-hotel-blocks/ Event information: https://bit.ly/vcfe2026site Jeff Brace VCF East Showrunner

2 months, 1 week

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Tony Hoare (1934-2026)

by Christian Liendo

Turing Award winner and former Oxford professor Tony Hoare passed away last Thursday at the age of 92. https://blog.computationalcomplexity.org/2026/03/tony-hoare-1934-2026.html https://en.wikipedia.org/wiki/Tony_Hoare

2 months, 1 week

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DECnet-RT on OpenSIMH

by johnforecast＠comcast.net

I have been able to bring up the DECnet-RT images, that Jay posted a few weeks ago, on OpenSIMH. Below are my notes on how to get it running. John. Notes for getting DECnet-RT V2.1 running on OpenSIMH NOTE: DECnet-RT is a phase III system so it does not understand Phase IV areas and can only address nodes in the range 1 - 255. If you attach it so a Phase IV router (e.g. PyDECnet) it can be accessed as node nnn in the area that the router is in. If you are bringing it up as part of a larger network (e.g. HECnet) make sure you "own" it's address otherwise you may cause routing problems. I have tried running DECnet on most versions of RT-11 from 5.0 to 5.7. Any version after 5.4D has various problems with file/terminal I/O. The available images will only run on an unmapped system with background/foreground support. This means that everything; monitor, disk driver, DECnet and application must fit in 28KW. Later versions of RT-11 slighly increased the size of the monitor and/or disk drtiver so that NFT and FAL will not fit in memory. DECnet-RT requires features that are not provided in the distributed monitors so you will have to generate a new monitor (See RT-11 System Generation Guide). You can take all of the default answers except: "Do you want the single job monitor?" Answer N "Do you want device time-out support?" Answer Y "How many extra device slots do you want?" Answer 4 Once you are running the new monitor, copy all the files from the 3 RX50 floppy images (RX0808.IMG, RX0809.IMG and RX0810.IMG) to your system device: COPY/SYS DUx:*.* SY: The system is configured to use a DLV-11 (CSR 176500, vector 300, priority 5) for network access. Add the following lines to your OpenSIMH .ini file: SET CPU 11/23 SET DLI ENA LINES=1 SET DLO0 DATASET 8B ATTACH DLI LINE=0,SPEED=115200,CONNECT=<IP ADDR>:<PORT>;NOTELNET If you are attaching to PyDECDnet, the associated configuration line would be: circuit dl-0 DDCMP --mode tcp --local-port <PORT> where <IP ADDR> and <PORT> need to be set according to your network. The network configuration is in a file called "CETAB.MAC". We can use CFE (Configuration File Editor) to change the node name and address (in this case to node name RT11 at address 111): .R CFE File name <SY:CETAB.MAC>: CFE>LIST EXEC Executor permanent characteristics as of 00:00 Identification = ERC PDP-11/23 Name = ERC23, Address = 124 Host = 124, Maximum links = 4 CFE>DEFINE EXECUTOR NAME RT11 ADDRESS 111 HOST 111 IDENT "RT11 11/23" CFE>LIST EXEC Executor permanent characteristics as of 00:01 Identification = RT11 11/23 Name = RT11, Address = 111 Host = 111, Maximum links = 4 CFE>DEFINE NODE 112 NAME REMOTE CFE>EXIT The last DEFINE command defines nodes in your DECnet network so you can connect to them. To load DECnet: .ASSIGN SY NT .R NCP NCP>SET SYSTEM NCP>SET EXECUTOR STATE ON NCP>SHO EXEC Node volatile summary as of 00:00 Executor node = 111 (RT11) State = On, Identification = RT11 11/23 NCP>EXIT If you want to allow incoming connections run NJS (Network Job Spawner): .R NJS ?NJS-I-Network Job Spawner Active and then it will report each program activation. The following programs are available: NCP - Network Control Program NFT - Network File Transfer TLK - Interactive talk with another (remote) terminal RMT - Remote terminal (RSX) RVT - Remote terminal (VMS) CED - Dumps internal DECnet data structures (/AL dumps everything) The following servers are available: NML - Network Management Listener (use with NCP) FAL - File Access Listener (use with NFT) LOOPER - Loop testing (use with NCP LOOP NODE name)

2 months, 1 week

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Digital or Pulse Electronics with Trigger tubes?

by Holm Tiffe

Hi guys, Since Friedhelm build his Nixie clock with tube electronics in 2005: https://www.jogis-roehrenbude.de/Leserbriefe/Bruegmann-Digital-Roehren-Cloc… I'm more or less trying to build a "tube" Nixie clock with neon lamps and/or trigger tubes/thyratrons instead of vacuum triodes. In 2005 I told Friedhelm that this is a nice clock..but build the wrong way. To tube times one build dividers using monoflops and ring counters with decatrons and so on..not with vacuum tube Flipflops. We've calculated the energy costs for this tube clock of approx. 400 Deutschmarks in 2005, don't really want todo this today..especially for the country with the dumbest and worst energy politics world wide.. green ideology politicans here has blown up the worlds best and safest nuclear power plants to dust... ... Since I've got approx 1000 of small chinese neon bulbs in the meantime, I've tried to build Ring counters out of the neon lamps..it works, but not that good, since the differnece between the Ignition voltage and the Extinguishing voltage is to small on this tubes, the counters are unreliable. A few years ago some russian trigger tubes TX4b got available, that are small pencil tubes with only 3,5mA Ia max. Those tubes have a bad reputation in rossia because they where put in to the vertical deflection circuit of some soviet made black and white TV sets and it was a bad design, the tubes where overloaded and don't lasted for very long. Another type, the MTX-90 was more often suggested and used. After some years the box with the TX4b fell into my hands and I'm searches again in the russian Internet for possible uses of the TX4b in Ring counters..the circuit design depends on the parameters of the tubes and isn't really that simple. I've searched for examples and finally found some morse transmitter device with "digital electronics" build out of the TX4b tubes.. russians wrote that this thing was unreliable :-) Nevertheless I found what I'm searching for, an schematic and a description in russian, english and french. ..so I have an working ring counter here next to me on a breadboard. :-) There is still an MPSA42 used as an pulse former in the clock circuit that I want to change agains a trigger tube. I need an Ide of an circuit that gets triggered on approx. 30-40V and outputs an rectangle pulse of lets say 60V and 10-30µs duration to properly trigger the ring counter, using possibly only one trigger tube. I think no one knows that for now..but I'm very grateful for links to older literature on this topic. approximately in 2000 I'm parted out old hp tube counters, the displays where "thermometer Displays using 10 pcs. of neon lamps, one for each number. The counters used 4 12at7 type "digital" tubes (don't remember the exact type for now) with biquinary output to the neon lamps. Later hp counter modules used the very same schematics and the neons and one hybrid photoresistor module in front of the neons as decoder to drive nixie tubes. I've tried it already in the past with the neon bulb ring counters.. a cheap photoresistor in a balc schrink tube that was put onto the neon lamp can switch a nixie..it works flawlessly. Tried this on the TX4b .. works too. :-) ..other schematics ad an additional trogger tube for each nixie cathode..the effort pretty much explodes... Hope someone can help with some hints or links. Regards, Holm -- Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, Goethestrasse 15, 09569 Oederan, USt-Id: DE253710583 info(a)tsht.de Tel +49 37292 709778 Mobil: 0172 8790 741

2 months, 2 weeks

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[OT] Free dialup service

by me＠scifidan.com

An acquaintenance of mine, in the BBS world, has a zero-cost dialup service for anyone wishing to use it. Thought I'd spread the word. For dialup details, follow the link. I believe he said there are ninety nodes and may see five used at any given time. Ref: https://2600.network Enjoy, Daniel sysop | Air & Wave BBS finger | calcmandan(a)bbs.erb.pw

2 months, 2 weeks

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Re: DECnet-RT

by Robert Armstrong

> Paul Koning <paulkoning(a)comcast.net> wrote: > On the other hand, the even more obscure DECnet/8 was found a couple > of years ago. Its main limitation .... Besides being Phase-I, DECnet/8 is not a "complete" implementation. The only application provided is a console to console talk program that can only talk to other PDP-8 nodes. There's no FAL, CTERM/RTERM, NFT, NCP, or any of the other things you might expect. I think DEC expected customers to write their own RTS/8 and DECnet-8 applications. Bob

2 months, 2 weeks

5
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Stolen QBus & Unibus boards

by Doc Shipley

I learned tonight that someone cleaned out my storage unit, and part of their haul was a couple of cartons of DEC boards. I haven't dug up the itemized list but in there were several QBus VAX memory boards, a graphics adapter, a microVAX III board set, a couple of RQDX boards, both QBus and Unibus serial boards, Unibus SDI board sets, a BA123 cabinet, tk70 controllers, a couple of Ethernet boards... And a Mentec/93. If anyone unfamiliar approaches you about selling a big stash of DEC, please get all the info you can and call the police. Thank you. Doc

2 months, 2 weeks

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Re: Operating system, on punch cards

by Van Snyder

On Mon, 2 Mar 2026, Fred Cisin wrote: > With a couple thousands I mean several thousands. And drawerS and cabinetS > because we got several cabinetS with drawerS with our machine. One drawer > contains three trays that hold about 2000 cards each. > Download our files and count the card yourself! Download from where?

2 months, 2 weeks

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Re: Operating system, on punch cards?

by Paul McJones

As a student at UC Berkeley (1967-1971), I had a part-time job at the Computer Center, which ran a CDC 6400 under SCOPE. We punched cards, transferred them to magnetic tape, and used UPDATE to maintain logical decks. I personally used this technology while working on CAL SNOBOL and CAL TSS. Once we got CAL TSS far enough along to support development (on a second CDC 6400), we switched to Teletypes (a mixture of Model 33’s and Model 35’s). I still have source code for CAL SNOBOL because of archivists at U. of Arizona and U. of Texas, but most of the source code for CAL TSS was lost (listings survive). Paul McJones https://www.mcjones.org/CAL_SNOBOL/ https://caltss.computerhistory.org/

2 months, 2 weeks

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Looking for service info for a Wang 600

by swperk＠earthlink.net

Hello, I bought a Wang 600 in unknown operating condition, but it looked to be complete and undamaged. Unfortunately, the shipper used a "professional" shipping service that wrapped this calculator in a single layer of bubble wrap, put it in a single wall box, and filled the rest of the space with packing peanuts. The result was predictable. The rear and sides of the molded ABS case were completely shattered, the rear mounted fan was knocked off, the housing bent, and a fan blade broken off. Fortunately (if that's the right word) the chassis, cards, keyboard, and display all seem intact. To try to assess the extent of the damage, I would like to complete the removal of the plastic case but do not see how it is fastened to the chassis. Can anyone help? Also, any troubleshooting info would be appreciated! I already have the schematics, but I probably won't be needing them until I do some inspections and basic checks. Thanks, Stan

2 months, 2 weeks

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Operating system, on punch cards?

by Steve Lewis

So studying about 1960s operating systems recently, it occurred to me that the ASR-33 wasn't really "a thing" until the late 1960s. Yes, they technically existed since 1963, but even going through 1960s Datamation issues - you don't see a lot of ads or mention of ASR-33 until 1965. The IBM 1050 maybe existed in 1961 for the IBM 709, but even so - general thought is that CTSS (operating system) was largely initially developed using punch cards. So - are there any archives or collections of these original punch cards? Or are they essentially all gone/destroyed, since in general after some code was "perfected" it was likely then archived to tape? Anyway, apologies - it was just something that only recently occurred to me, that basically all of the original operating systems originated on punch cards: CTSS, Supervisor, AOSP, SCOPE, even MULTICs. So - do any of those decks of cards still exist in archive? Would be neat to see a photo of those - except it would be a shoebox of punch cards like any other, I suppose. Or is this wrong, and the top tier teams making these OS's, probably had teletypes and all the magnetic tape they wanted? -Steve

2 months, 2 weeks

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Everex Step/MP: Did it ship?

by Chris Zach

So back in the 1990's the dream server for me was an Everex system called the Step/MP. Cube shaped, EISA bus, could take multiple 386/33 CPU blades and ran SCO. But all I had was memories as there was very little info on the Net. Today I was going through a closet I haven't been able to access for 20 years and in the Computerworld 1992 25'th anniversary issue I found it: A 2 page monster ad about the Step/MP. $13k, could have six 486/33 CPUs, EISA/ISA bus, 64mb of memory stock with support for 4mb SIMMs. So it did exist.... Question is did any of them make it out there? SCO was the obvious OS, but given that it was a SMP system I wonder if there was an NT 4.0 HAL out there like there was for the NCR 3550/4300 series of multiprocessor systems. Anyone have one? Seen one in the wild? I am curious. Everex/STEP was always the best quality system for a server, right alongside Compaq. Sad they went out of business. Chris

2 months, 2 weeks

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Looking for Codex modem manuals/info

by Richard Cini

All – I’m working on a simulation project where I’m using two Codex 2121 LDSU (local data service unit) modems to simulate a leased line setup to a DECSYSTEM-2020. These modems use 2-pair cabling (TX+,TX-/RX+.RX-) and DCE DB25 connections. I believe each modem is working in loopback mode, but I can’t get it to work over the 2-pair interface between the modems (i.e., a loop back plug on one modem and terminal on the other). The only manual I’ve been able to locate is the sales brochure, not any kind of user manual. Anyway, have the interface cross-connected (i.e., TX to RX) but there are no polarity markings so I just used each pair in the same color order. Has anyone used this kind of modem before, have a manual, or know how to connect them? Thanks! Rich -- Rich Cini http://cini.classiccmp.org https://github.com/RichCini

2 months, 2 weeks

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Re: Your subscription for cctalk mailing list has been disabled

by Alessandro Mazzini

Test ( sorry guys for cluttering , but I'm puzzled since I'm using Hotmail so... should not have this kind of issues ) -----Original Message----- From: cctalk-bounces(a)classiccmp.org <cctalk-bounces(a)classiccmp.org> Sent: Monday, March 2, 2026 7:03 AM To: mazzini_alessandro(a)hotmail.com Subject: Your subscription for cctalk mailing list has been disabled Your subscription has been disabled on the cctalk(a)classiccmp.org mailing list because it has received a number of bounces indicating that there may be a problem delivering messages to mazzini_alessandro(a)hotmail.com. You may want to check with your mail administrator for more help. If you have any questions or problems, you can contact the mailing list owner at cctalk-owner(a)classiccmp.org

2 months, 3 weeks

2
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Re: Operating system, on punch cards?

by bluewater emailtoilet.com

Punchcards? You want punchcards? I got punchcards. Not exactly what I think you are looking for but a large sample. Please check out www.punchcardarchive.com Check the Stats page for a quick summary. Beware the Album page. It takes a while to load. After all, it has to display 25532 cards. Not a full program but doing a search on CCROS in the Title field will show a few cards that represent a few bits of a read only S/360 program. Donald

2 months, 3 weeks

1
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Identifying This Component from VT100 Monitor Board

by Robert Jarratt

I asked this before a few years ago but didn't come to a firm conclusion. The two parts are shown in this picture: https://rjarratt.wordpress.com/wp-content/uploads/2023/12/img_20231221_1123… They are from a VT100 Monitor board. There is no schematic for my version of the board, but a related schematic is on p58 of this schematic: https://bitsavers.org/pdf/dec/terminal/vt100/MP00633_VT100_Schematic_Feb82.…. They are labelled Q414 and CR406, but the Feb 82 revision uses a different board and those two parts are in TO-220 packages rather than TO-3 as here.. I have removed both of them and tested them with a DMM. Neither of them measure as two diodes, they do not measure open circuit in any direction, so either they are both faulty or they are not transistors (unlikely). I have found a spec for a 2SB411 at https://alltransistors.com/transistor.php?transistor=10279. This seems to be a germanium transistor. When I last asked about this I had a conversation with Tony Duell, who was very sceptical that these could be germanium transistors, so naturally I am very doubtful that they are 2SB411 transistors. However, in the schematic Q414 is shown as NPN, the 2SB411 is PNP and this seems to match the way the part is connected on my board (Collector to HORIZ GND). I am working on a reverse engineered schematic. Can anyone tell me what these components are so I can find a datasheet for them? Better still a suggested replacement would be really helpful, especially if they are 2SB411s because they seem to be hard to find. Thanks Rob

2 months, 3 weeks

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Re: DECnet-RT

by Jacob Ritorto

Nice, Jay! Thank you > On Feb 22, 2026, at 18:44, Jay Jaeger <cube1(a)charter.net> wrote: > > On 2/21/2026 9:27 AM, Jacob Ritorto via cctalk wrote: >> Hiya. >> Is DECnet for RT-11 still lost? If not, anyone got a link to it? >> thx >> jake > > I may have *SOME* of it. I have three RX50's and one RX02 that have some DECNet RT V2.1 files. They are NOT distribution disks, and the disks have hand-written labels, so they might not even contain what the handwritten label indicates - I have not checked them out under SimH. > > Anyway, I just put them in my "bitsavers contribution" area of my Google Drive, and they can be found on my Google Drive at: > > https://drive.google.com/drive/folders/1fiOScGSpvLiVQ0yyOg2yC5EpqRKiKWQ5?us… > > JRJ

2 months, 3 weeks

5
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DECnet-RT

by Jacob Ritorto

Hiya. Is DECnet for RT-11 still lost? If not, anyone got a link to it? thx jake

2 months, 3 weeks

8
13
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NRAO Data tapes

by Dani Werts

Hello, I'm an employee with the National radio astronomy observatory here in Socorro New Mexico. As part of our NGVLA upgrades, we are seeking to get rid of old data tapes from the tape reel days of Computing. These contain things such as the boot loaders, OS, specific collection programs and antenna movement programs. I personally would hate to see these just wind up in the literal dumpster and would like to see them sent out to a museum or an archiving body that can preserve them and keep them safe as a dynamic part of history. If anyone is interested or knows someone who would be interested in the VLAs data tape library please let me know. V/R Danielle Werts Front end engineer VLA Socorro New Mexico

2 months, 4 weeks

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Recommendations for 8051 software tools?

by Paul Flo Williams

I've started working on a disassembly of the Digital VT320 video terminal, so I'm diving into 8051 assembler. At the moment, I'm using the D52 disassembler and am getting decent results, although I wished I hadn't used the analyse option to produce a starting control file; it doesn't cope at all well with code involving lots of jump tables because the control flow appears to break, and it decides that much of the code is just data. Ho hum. Nevertheless, the code looks pretty understandable at the moment, so the next stage is to annotate by hand, instead of updating the control file, and to assemble whenever I make a change so that I can be sure that I can produce the original ROM. There isn't an "A52" to match D52, so I was wondering if anyone has recommendations for a FOSS macro assembler that will take D52's output. I ask for a macro assembler because there are some modifications I'd like to make to the source file to clear things up. One of these would be to cope with the fact that DEC decided that all of their jump tables would have addresses in little-endian format, despite the 8051 being a big-endian device. So, the normal "dw" directive is not going to work for me, and I'll need to do something like: dwl macro %1 db low(%1), high(%1) endm (Totally pulling that syntax out of my bum, btw.) A quick search finds as31 and naken_asm - anyone use these? I'd also love to hear recommendations for emulator code for the 8051, preferably simple C because I'm going to need to hook up a 2681 DUART, 5911 EEPROM and DC7081 video chip (all presumably new code) to get this working. Paul.

2 months, 4 weeks

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Re: Everex Step/MP: Did it ship?

by Chris Zach

On 2/21/26 07:48, emanuel stiebler wrote: > Everex had their own Unix version (5.4?), "ESIX" which ran on intel. > Probably they ran that? No, it ran SCO Unix, which was the business version popular at the time. I found the ad and edition of computerworld in the Internet Archive: The issue is the June 22nd 1992 one and it has all sorts of interesting articles and predictions from people like Gates, Jobs, Wang, Bell, and others. Going to be worth a read here. Anyway, on the PDF download it starts at page 186-189. They benchmarked it against a Dec 433MP (could also do 6 processors) and a SystemPro (2) with 60 user loads. Wow.

3 months

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Wyse 520

by me＠scifidan.com

A buddy of mine showed off his Wyse 520 and was wondering if anyone on here has one and if you use it. It's a nice looking keyboard but I'm not that fond of the small screen. Daniel sysop | Air & Wave BBS finger | calcmandan(a)bbs.erb.pw

3 months

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Sun 386i ROM/Firmware image?

by Michael Engel

Hi, did anyone ever create an image of the Sun 386i firmware (EP)ROM? There was a discussion on cctalk two years ago, but it seems the ROM was not dumped back then. https://marc.info/?l=classiccmp&m=171014099801502 The firmware dump would obviously be very useful to write an emulator for the 386i. Our department here at Bamberg Uni bought four 386i machines back in 1989 as their first workstations for a whooping 230k German Marks. It would be nice to be able to show a running machine or an emulation at our upcoming anniversary (the department itself was only founded 25 years ago, but the 386i machines were purchased more than a decade before that date by the people who later founded the department), but none of the 386i machines here have survived.. So if someone has a 386i for sale (ideally in Europe, I'm in Germany) I'm also interested... Best, Michael

3 months

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Re: Recommendations for 8051 software tools?

by trp

What timing! I’ve been down the 8051 rabbit hole for a few months now. I cut my professional teeth on Intel assembler back in the mid 80’s so. Never worked with the 8051 (8048/8085/8086/8088 were the processors I used). What I’ve found so far that may be of use are: SDCC (Small Device C Compiler). It has an assembler, sdas. I haven’t used it. I also found the original Intel Macs-51 tools (macro assembler, linker, librarian). I probably prefer the Intel tools because they remind me of the tools I used way back when. The Intel DOS tools will run on msdos emulators, dosbox-x is one I found useful. It is possible to run dosbox-x without the gui (set up the DOS commands in the autoexec.bat) dosbox-x -silent -nomenu The Intel DOS tools are located here: https://www.retrocomputing.nl/wp-content/uploads/PLM-51/PLM51_V1_2.zip https://www.retrocomputing.nl/wp-content/uploads/PLM-51/PLM51_V1_4.zip Intel documentation can be found with an internet search at a number of sites. The relevant titles are: MCS-51 MACRO ASSEMBLER USER'S GUIDE MCS-51 UTILITIES USER’S GUIDE FOR DOS SYSTEMS EXTERNAL PRODUCT SPECIFICATION FOR THE MCS-51 OBJECT MODULE FORMAT The msdos emulator is here: https://github.com/joncampbell123/dosbox-x/releases/tag/dosbox-x-v2026.01.02 I ran into problems building SDCC from the “official” repo. I used the following repo sucessfully: https://github.com/swegener/sdcc.git

3 months

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Re: Chat program for RSX

by Vasile Buruiana

I hope this message arrives in the proper talking group as it is my first reply within years of reading everything. If you are getting chastised for using an old computer, just tell everybody that even the worst modern virus of today does not fit inside the RAM of your dinosaur, so you are 99.99% protected. Security through obscurity. Ask your colleagues if they have the same level of protection given only by the existence of any of their systems, and no other additional software. I am writing this from an old terminal connected to a FELIX C-256 Romanian made mainframe from the 1970s. That is a clone of the French IRIS-50 made by Companie Internationale pour Informatique. Now that's an ugly beast. Try to telnet to some modern small system running some BSD / Linux, which talks to the world, then use BitchX or some other text-based IRC client to chat. I am sorry I am in a hurry, big boss at work wants his paperwork done. Best regards Vasile Buruiana Doctor of communist digital dinosaurs On Mon, Feb 16, 2026 at 8:00 PM <cctalk-request(a)classiccmp.org> wrote: > Send cctalk mailing list submissions to > cctalk(a)classiccmp.org > > To subscribe or unsubscribe via email, send a message with subject or > body 'help' to > cctalk-request(a)classiccmp.org > > You can reach the person managing the list at > cctalk-owner(a)classiccmp.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of cctalk digest..." > > Today's Topics: > > 1. Chat program for RSX (Jacob Ritorto) > 2. Re: Chat program for RSX (Daniel Seagraves) > 3. Re: Chat program for RSX (emanuel stiebler) > 4. Re: Chat program for RSX (ben) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Mon, 16 Feb 2026 00:47:31 -0500 > From: Jacob Ritorto <jacob.ritorto(a)gmail.com> > Subject: [cctalk] Chat program for RSX > To: cctalk(a)classiccmp.org > Message-ID: <CA5293FC-836F-4D0C-AE16-9404CF0E7E8A(a)gmail.com> > Content-Type: text/plain; charset=utf-8 > > Hi, > > I like period correct hardware terminals for authentic immersion feels and > have been tending to RSX (and UNIX) PDP-11s since my teen years, quite a > long time now. I keep them in my living room and den, etc. Convincing > setups that quite look the part. And actually *are* the part; running much > as though it’s still 1986. Very little emulation “cheating.” Real SMD > disks, even, sometimes. > > Anyway, one of the many fun things I do with them is chat rooms. People > are like, “you connected here on a WHAT?” > > In doing this I find myself often chastised by my esteemed Internet > colleagues for using such “horrible” computers because “That’s the worst > possible computer you could pick” (real quote, minus some aspersions about > power consumption) and “what loser can’t scroll up and look through chat > that’s more than 24 lines back?!?” > > I try to ignore all this in the name of “progress,” but, I mean, they have > a point. As much as I’m having a nice time with all this, it does hurt > quite enough already for all the other obvious reasons and then I CAN’T > SCROLL BACK?!? Come on. > > When you think about it retrospectively, this _is_ actually kind of bad, > right? > > So What? Quit the real terminal and computer and use a modern laptop? > > Hell no. > > It strikes me that scrollback is a silly thing to condemn such a storied > lineage of computers over, but that’s exactly what’s happening in this > contemporary vale of tears. My friends think PDP-11s suck because they > can’t scroll (and, yes, perhaps some other things). > > So I say let’s write a scrolling “terminal” program for RSX. Should work > with serial and telnet (BQT stuff) and DECnet (i.e. $SET HOST XXXXXX). > Actually maybe it doesn’t even have to know about that layer, right? > (Thinking as I write this). Spawn whatever command and it buffers the > output such that you can effortlessly scroll back up through stuff that has > scrolled past. > > Something terribly rudimentary, perhaps, but with at least infinite > scrollback. Like just a dumb scroll back buffer wrapper thing. Writes to > / reads from disk as you accrue characters / cursor up. > > Heck, this would have been a boon in the day for normal use, right? Like > having a glass tty and a real paper printing terminal all in one! I can > scarcely believe it doesn’t already exist. > > Would you folks be into helping with it? If not, I’ll try myself. Did a > bit of this sort of work some decades ago writing a disk imager under RSX > in MACRO-11 using QIO$ calls, looked up fresh from the orange binders > sitting there on the couch. Pretty easy. > > Should we take from screen or tmux? Or do a clean room concept, you think? > I hope it can work under RSX and UNIX. RSTS/e, too, anyone? RT? > > If you have opinions about this or if it already exists, let me know, pls. > > thx > jake > > ------------------------------ > > Message: 2 > Date: Mon, 16 Feb 2026 07:57:48 -0600 > From: Daniel Seagraves <dseagrav(a)lunar-tokyo.net> > Subject: [cctalk] Re: Chat program for RSX > To: "General Discussion: On-Topic and Off-Topic Posts" > <cctalk(a)classiccmp.org> > Message-ID: <6656C51C-12BD-4D8F-8419-C82A0439A88F(a)lunar-tokyo.net> > Content-Type: text/plain; charset=utf-8 > > > > > On Feb 15, 2026, at 11:47 PM, Jacob Ritorto via cctalk < > cctalk(a)classiccmp.org> wrote: > > > > Hi, > > > > I like period correct hardware terminals for authentic immersion feels > and have been tending to RSX (and UNIX) PDP-11s since my teen years, quite > a long time now. I keep them in my living room and den, etc. Convincing > setups that quite look the part. And actually *are* the part; running much > as though it’s still 1986. Very little emulation “cheating.” Real SMD > disks, even, sometimes. > > > > Anyway, one of the many fun things I do with them is chat rooms. People > are like, “you connected here on a WHAT?” > > > > In doing this I find myself often chastised by my esteemed Internet > colleagues for using such “horrible” computers because “That’s the worst > possible computer you could pick” (real quote, minus some aspersions about > power consumption) and “what loser can’t scroll up and look through chat > that’s more than 24 lines back?!?” > > > > I try to ignore all this in the name of “progress,” but, I mean, they > have a point. As much as I’m having a nice time with all this, it does > hurt quite enough already for all the other obvious reasons and then I > CAN’T SCROLL BACK?!? Come on. > > If you have a decwriter or teletype instead of a glass tty, your scroll > back is however much paper you can keep around. > > > > ------------------------------ > > Message: 3 > Date: Mon, 16 Feb 2026 09:16:34 -0500 > From: emanuel stiebler <emu(a)e-bbes.com> > Subject: [cctalk] Re: Chat program for RSX > To: "General Discussion: On-Topic and Off-Topic Posts" > <cctalk(a)classiccmp.org> > Message-ID: <c0be7865-5bb1-4d7a-8b2d-cbb9955549e0(a)e-bbes.com> > Content-Type: text/plain; charset=UTF-8; format=flowed > > On 2026-02-16 08:57, Daniel Seagraves via cctalk wrote: > > > > > >> On Feb 15, 2026, at 11:47 PM, Jacob Ritorto via cctalk < > cctalk(a)classiccmp.org> wrote: > >> > >> Hi, > >> > >> I like period correct hardware terminals for authentic immersion feels > and have been tending to RSX (and UNIX) PDP-11s since my teen years, quite > a long time now. I keep them in my living room and den, etc. Convincing > setups that quite look the part. And actually *are* the part; running much > as though it’s still 1986. Very little emulation “cheating.” Real SMD > disks, even, sometimes. > >> > >> Anyway, one of the many fun things I do with them is chat rooms. > People are like, “you connected here on a WHAT?” > >> > >> In doing this I find myself often chastised by my esteemed Internet > colleagues for using such “horrible” computers because “That’s the worst > possible computer you could pick” (real quote, minus some aspersions about > power consumption) and “what loser can’t scroll up and look through chat > that’s more than 24 lines back?!?” > >> > >> I try to ignore all this in the name of “progress,” but, I mean, they > have a point. As much as I’m having a nice time with all this, it does > hurt quite enough already for all the other obvious reasons and then I > CAN’T SCROLL BACK?!? Come on. > > > > If you have a decwriter or teletype instead of a glass tty, your scroll > back is however much paper you can keep around. > > > > THAT'S the vintage spirit! ;-) > > ------------------------------ > > Message: 4 > Date: Mon, 16 Feb 2026 09:55:41 -0700 > From: ben <bfranchuk(a)jetnet.ab.ca> > Subject: [cctalk] Re: Chat program for RSX > To: cctalk(a)classiccmp.org > Message-ID: <28c01576-53b9-4478-aea2-74ddb54bb225(a)jetnet.ab.ca> > Content-Type: text/plain; charset=UTF-8; format=flowed > > On 2026-02-16 7:16 a.m., emanuel stiebler via cctalk wrote: > > On 2026-02-16 08:57, Daniel Seagraves via cctalk wrote: > >> > >> > >>> On Feb 15, 2026, at 11:47 PM, Jacob Ritorto via cctalk > >>> <cctalk(a)classiccmp.org> wrote: > >>> > >>> Hi, > >>> > >>> I like period correct hardware terminals for authentic immersion > >>> feels and have been tending to RSX (and UNIX) PDP-11s since my teen > >>> years, quite a long time now. I keep them in my living room and den, > >>> etc. Convincing setups that quite look the part. And actually *are* > >>> the part; running much as though it’s still 1986. Very little > >>> emulation “cheating.” Real SMD disks, even, sometimes. > >>> > >>> Anyway, one of the many fun things I do with them is chat rooms. > >>> People are like, “you connected here on a WHAT?” > >>> > >>> In doing this I find myself often chastised by my esteemed Internet > >>> colleagues for using such “horrible” computers because “That’s the > >>> worst possible computer you could pick” (real quote, minus some > >>> aspersions about power consumption) and “what loser can’t scroll up > >>> and look through chat that’s more than 24 lines back?!?” > >>> > >>> I try to ignore all this in the name of “progress,” but, I mean, they > >>> have a point. As much as I’m having a nice time with all this, it > >>> does hurt quite enough already for all the other obvious reasons and > >>> then I CAN’T SCROLL BACK?!? Come on. > >> > >> If you have a decwriter or teletype instead of a glass tty, your > >> scroll back is however much paper you can keep around. > >> > > > > THAT'S the vintage spirit! ;-) > Punched cards :) > > > End of cctalk Digest, Vol 1123, Issue 1 > *************************************** >

3 months

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Chat program for RSX

by Jacob Ritorto

Hi, I like period correct hardware terminals for authentic immersion feels and have been tending to RSX (and UNIX) PDP-11s since my teen years, quite a long time now. I keep them in my living room and den, etc. Convincing setups that quite look the part. And actually *are* the part; running much as though it’s still 1986. Very little emulation “cheating.” Real SMD disks, even, sometimes. Anyway, one of the many fun things I do with them is chat rooms. People are like, “you connected here on a WHAT?” In doing this I find myself often chastised by my esteemed Internet colleagues for using such “horrible” computers because “That’s the worst possible computer you could pick” (real quote, minus some aspersions about power consumption) and “what loser can’t scroll up and look through chat that’s more than 24 lines back?!?” I try to ignore all this in the name of “progress,” but, I mean, they have a point. As much as I’m having a nice time with all this, it does hurt quite enough already for all the other obvious reasons and then I CAN’T SCROLL BACK?!? Come on. When you think about it retrospectively, this _is_ actually kind of bad, right? So What? Quit the real terminal and computer and use a modern laptop? Hell no. It strikes me that scrollback is a silly thing to condemn such a storied lineage of computers over, but that’s exactly what’s happening in this contemporary vale of tears. My friends think PDP-11s suck because they can’t scroll (and, yes, perhaps some other things). So I say let’s write a scrolling “terminal” program for RSX. Should work with serial and telnet (BQT stuff) and DECnet (i.e. $SET HOST XXXXXX). Actually maybe it doesn’t even have to know about that layer, right? (Thinking as I write this). Spawn whatever command and it buffers the output such that you can effortlessly scroll back up through stuff that has scrolled past. Something terribly rudimentary, perhaps, but with at least infinite scrollback. Like just a dumb scroll back buffer wrapper thing. Writes to / reads from disk as you accrue characters / cursor up. Heck, this would have been a boon in the day for normal use, right? Like having a glass tty and a real paper printing terminal all in one! I can scarcely believe it doesn’t already exist. Would you folks be into helping with it? If not, I’ll try myself. Did a bit of this sort of work some decades ago writing a disk imager under RSX in MACRO-11 using QIO$ calls, looked up fresh from the orange binders sitting there on the couch. Pretty easy. Should we take from screen or tmux? Or do a clean room concept, you think? I hope it can work under RSX and UNIX. RSTS/e, too, anyone? RT? If you have opinions about this or if it already exists, let me know, pls. thx jake

3 months

4
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Passing of Robert Tinney

by Murray McCullough

I read a day or so ago that Robert Tinney passed on. I enjoyed his cover-page art on Byte as I’m sure so many more did too. He illustrated in a more-than-impressive way & detail what early microcomputing was. May the computer gods bless him. Murray--

3 months

1
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CMS Pipelines for UNIX

by Lyndon Nerenberg (VE7TFX/VE6BBM)

Okay, third attempt at this, this time with the appropriate Subject header. --lyndon ------- Forwarded Message From: Adam Thornton <athornton(a)gmail.com> Date: Thu, 5 Dec 2024 09:55:30 -0700 Message-ID: <CAP2nic0E=0dLT2JaDJv0OCBQUBaqKd6+2hy30hpKjowPVc76BA(a)mail.gmail.com> To: The Eunuchs Hysterical Society <tuhs(a)tuhs.org> Subject: [TUHS] Re: Pipes (was Re: After 50 years, what has the Impact of Unix been?) List-Id: The Unix Heritage Society mailing list <tuhs.tuhs.org> On Thu, Dec 5, 2024 at 8:20=E2=80=AFAM Dan Cross <crossd(a)gmail.com> wrote: > > Unix pipelines, on the other hand, tend to be used in a manner that is > strictly linear, without the fan-out and fan-in capabilities described > by Morrison. Of course, nothing prevents one from building a > Morrison-style "network" from Unix processes and pipes, though it's > hard to see how that would work without something like `select`, which > didn't yet exist in 1978. Regardless, Unix still doesn't expose a > particularly convenient syntax for expressing these sorts of > constructions at the shell. > > Rick Troth has recently published xfl, which is pretty much CMS Pipelines for Unix. https://github.com/trothtech/xfl He's got a slide deck on it at http://www.casita.net/pub/xfl/pervasive-vmws-2024.pdf . There are a lot of really cool things you can do with fanin/fanout. Adam

3 months, 1 week

2
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Inquiry regarding Noel Chiappa / Status of Computer History Wiki (Gunkies.org)

by Hans-Ulrich Hölscher

Dear list members, I am writing to this list as I am concerned about J. Noel Chiappa. I have noticed that the Computer History Wiki has been locked for maintenance ("Spam issue") for some time now. As Noel is the primary administrator and heart of the site, this persistent lock, combined with the fact that he hasn't responded to my recent emails, makes me worry about his well-being - especially knowing that he has been facing health challenges. Does anyone on this list have recent information on how he is doing or if there is any update regarding the status of the wiki? I am not looking for private details, but simply a sign that he is okay or if there is anything the community is currently doing to support his projects. You can of course send me a PM if you like. Thank you for any insights you might be able to share. Best regards, Ulli Hölscher aka "VAXorcist"

3 months, 1 week

2
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CMS Pipelines for UNIX

by Lyndon Nerenberg (VE7TFX/VE6BBM)

Some people have passively accused me of making this up :-) Here is the original announcement from the TUHS list. --lyndon

3 months, 1 week

2
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7" 9 Track 1600 BPI Tapes free (local pickup or cost of S&H)

by Ali

I have a bunch of what looks to be 7" 9 Track 1600 BPI tapes based on the labels. I have no use for them, before I trash them is anyone interested in them for the princely sum of S&H/prepaid label or you can pick them up for free in Upland, CA. I will hold on to them until 2-20-26 at which point I will toss them. Thanks. https://forum.vcfed.org/index.php?threads/9-track-1600-bpi-7-tapes-free.1256 372/ -Ali

3 months, 1 week

1
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[TUHS] Re: Pipes (was Re: After 50 years, what has the Impact of Unix been?) (fwd)

by Lyndon Nerenberg (VE7TFX/VE6BBM)

Hmm ... the list manager apparently stripped the MIME attachment. Here it is again inline. --lyndon ------- Forwarded Message From: Adam Thornton <athornton(a)gmail.com> Date: Thu, 5 Dec 2024 09:55:30 -0700 Message-ID: <CAP2nic0E=0dLT2JaDJv0OCBQUBaqKd6+2hy30hpKjowPVc76BA(a)mail.gmail.com> To: The Eunuchs Hysterical Society <tuhs(a)tuhs.org> Subject: [TUHS] Re: Pipes (was Re: After 50 years, what has the Impact of Unix been?) On Thu, Dec 5, 2024 at 8:20=E2=80=AFAM Dan Cross <crossd(a)gmail.com> wrote: > > Unix pipelines, on the other hand, tend to be used in a manner that is > strictly linear, without the fan-out and fan-in capabilities described > by Morrison. Of course, nothing prevents one from building a > Morrison-style "network" from Unix processes and pipes, though it's > hard to see how that would work without something like `select`, which > didn't yet exist in 1978. Regardless, Unix still doesn't expose a > particularly convenient syntax for expressing these sorts of > constructions at the shell. > > Rick Troth has recently published xfl, which is pretty much CMS Pipelines for Unix. https://github.com/trothtech/xfl He's got a slide deck on it at http://www.casita.net/pub/xfl/pervasive-vmws-2024.pdf . There are a lot of really cool things you can do with fanin/fanout. Adam

3 months, 1 week

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Robert Tinney the man who created many of the early Byte Covers passed away.

by Christian Liendo

https://tinney.net/in-memoriam Robert Frank Tinney, of Washington, Louisiana, passed away peacefully at River Oaks Nursing & Rehabilitation Center on February 1st, 2026, at the age of 78. Born in 1947 in Penn Yan, New York, Robert moved at a young age with his parents, Ellis and Ruby, and his younger brother, Bill, to Baton Rouge, Louisiana. From Istrouma High School, Robert took with him a diploma, life-long friendships and a focus on artistic expression to Louisiana Tech University to study illustration and graphic design in commercial art. After graduating, and after a tour of service during the Vietnam War, Robert began a career that would see his artwork don the covers and pages of some of the most well-known computing publications in the world, most notably BYTE Magazine. Due to his signature artistic style, the name Robert Tinney soon became synonymous with the rapidly-growing world of computing technology, and remains so to this day. A deeply caring husband and family man, Robert is survived by his devoted wife of 48 years, Susan, three children, nine grandchildren and one great-grandchild. Married in 1978, Robert and Susan lived and worked in Baton Rouge until 1987, when they moved to Washington, Louisiana, where they would restore an historic landmark home, the Crawford House. For over four decades, Robert and Susan served and nurtured their beloved community with open arms, and were rewarded with priceless family memories and an exuberance of rich, cherished friendships. Robert’s philosophical intellect, refreshing humor and profoundly sympathetic nature will be sorely missed by his loving family and a wealth of loyal friends and admirers. A celebration of Robert’s life will be held in May, 2026. For more information, RSVP to illustrations(a)tinney.net.

3 months, 1 week

4
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Glen Ellyn CCC meeting - March 28th

by Mike Katz

The next Glen Ellyn CCC chat and repair meeting will be held on March 28th, 2026. Anytime after 2PM until we all get to tired to solder and talk. We will order Pizza around 5:30pm. As usual Beer and Pop will be provided. 385 Saint Charles Rd Glen Ellyn, IL 60137 +1 (773) 414-1044 (Cell)

3 months, 1 week

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PDP-8 software for the DEC MPS (MIcroProcessor System)?

by Robert Armstrong

Short version - I'm looking for copies of the PDP-8 software for the DEC MPS, MIcroProcessor System. Longer form, since it wasn't very well known - DEC made an 8008 (yes, 8008, not 8080) microprocessor based system on a set of three quad sized modules, plus a really nifty looking lights and switches front panel. It's not clear what DEC expected customers to do with it; I guess use it to build an embedded control system for things that were too simple for a PDP-8 or -11. In any case, DEC made a whole software development toolchain for the MPS and 8008 using a PDP-8 as a host computer. There was a cross assembler (aka MPA), a downloader (aka MPL), a specialized text editor (yes, MPE), a debugger (you guessed it - called MPD), a EPROM programmer, and several other miscellaneous tools. They were all distributed on paper tape and I believe they were intended to run on a basic 8/E and Teletype, without mass storage and without OS/8. If anybody has these, I'd love to get copies of the tape images. Thanks, Bob

3 months, 1 week

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Equipment still available in Upland, CA

by Ali

The following stuff is still available before they go landfill. Prices are highly negotiable. I am mostly interested in getting them to good homes... Sony StorStation AIT Library LIB-162 https://forum.vcfed.org/index.php?threads/sony-storstation-ait-library-lib-1 62.1253656/ HP SureStore SC10 https://forum.vcfed.org/index.php?threads/hp-surestore-sc10.1253657/ HP Impact Line Printer 2563C (this is one nice printer and if I had the room I would keep it but alas....) https://forum.vcfed.org/index.php?threads/hp-impact-line-printer-2563c.12536 54/ Gateway 2000 Vivitron 17" SVGA Monitor https://forum.vcfed.org/index.php?threads/gateway-2000-vivitron-17.1253804/ -Ali

3 months, 1 week

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Datapoint 2200 emulator and CTOS

by Steve Lewis

I just came across this today, it looks like work that came about around January 2024 by Mattis Land. Mattis, not sure if you're active here, but this is really great work! The emulator code is here: https://github.com/MattisLind/DP2200/ An Unlisted demo of the emulator in action is here (running some CTOS software): https://www.youtube.com/watch?v=XfsMBhP13ww Might this CTOS be the only operating system fit on an audio cassette tape? -Steve

3 months, 1 week

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Re: Equipment still available in Upland, CA

by swperk＠earthlink.net

Hi Ali, I just replied to you through the vcfed forum. My posting is being moderated (likely because I'm an infrequent poster) but I am interested in your HP 2563C printer. Stan

3 months, 1 week

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Random PCI/AGP cards, WinTV, ES1371 sound etc (UK)

by David Brownlee

I find my collection of random old cards overflowing and I have picked out six random PCI/AGP cards on the offchance anyone is interested - Hauppauge PCI WinTV - ES1371 AudioPIC (x 2) - PCI Audio/modem card - ATI AGP Rage Pro 109-73100-02 - ATI Radeon 9550 128M AGP Images at https://postimg.cc/gallery/Y7PRkCG Are the cards of any interest to people? (for the price of postage or collection from London, UK :) I may also have a phenom 9550 with its motherboard, some and a selection of PCI plus IDE/SATA network cards - let me know if I should go digging... David

3 months, 2 weeks

1
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Interesting stuff on FB Marketplace

by Anders Nelson

Dahlgren Wizard II engraver with amber CRT: https://www.facebook.com/share/16A9ZxVzvP/ Apple IIc: https://www.facebook.com/share/1ay7RLn6ZY/ Anything with a green or amber CRT will catch my attention haha. -- Anders Nelson

3 months, 2 weeks

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Re: Robert Tinney the man who created many of the early Byte Covers passed away.

by John Foust

At 06:17 AM 2/6/2026, Christian Liendo via cctalk wrote: >https://tinney.net/in-memoriam > >Robert Frank Tinney, of Washington, Louisiana, passed away peacefully I remember meeting him at a COMDEX or maybe a West Coast Computer Fair once upon a time. He was selling prints. I recognized him. His booth wasn't getting the traffic it deserved! - John

3 months, 2 weeks

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Computer history events in Europe in 2026?

by Bill Degnan

Looking for recommendations for a non-US computer festival or event in 2026, see if I can fit into my travel plans this year Suggestions? Thanks Bill

3 months, 2 weeks

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Re: Identifying This Component from VT100 Monitor Board

by Brent Hilpert

On 2026Feb 2,, at 11:00 PM, Rob Jarratt <robert.jarratt(a)ntlworld.com> wrote: > > I forgot to reply to this one. Thanks Brent. > > Of particular interest is the description of how the monitor board is supposed to work in the VT180 TM at page 6-102. When I have time I will check it carefully, I think there may be clues about Q414. Interestingly the intro says that horizontal section is not intuitively understandable from an examination of the schematic and it is a likely candidate for failure because of high stresses in the components. I forgot some th-of-op was also included there, and then found it again tonight in another document: vt100.net <http://vt100.net/> has a work-in-progress html version of some VT100 Technical manual: https://vt100.net/docs/vt100-tm/ <https://vt100.net/docs/vt100-tm/> There doesn’t seem to be a document date there but Chapter 4 has that th-of-op section on the Elston monitor: https://vt100.net/docs/vt100-tm/chapter4.html <https://vt100.net/docs/vt100-tm/chapter4.html> Section 4.8 Neither of course has the schematic, but notably these th-of-op sections reference component IDs that match the PCB & your RE'd schematic, and the small th-of-op diagrams do show Q414 as PNP. The T403 pin numbers there differ from your labeling as Digital/Elston viewed it as 6-pin with 1 & 5 absent, rather than 4-pin. Your pics show what appear to be some date codes from 1979. The vt100.net <http://vt100.net/> website is aware of other field printsets from 1979: https://vt100.net/manx/part/dec/mp-00633-00/ <https://vt100.net/manx/part/dec/mp-00633-00/> but they also cannot find them. So it does appear that, in addition to the Ball monitors, there were two versions of the Elston monitor for the VT100: - one from 1979 with PNP HOT, - one from 1982 modified to NPN HOT (along with other mods) (per MP00633_VT100_Schematic_Feb82.pdf) Double-checking with the pics, your schematic looks correct to me regarding the HOT circuit. Looks like the board could be modified for NPN with 1 ~ 3 trace cuts depending on how one went about heatsinking the HOT. Or use the search specification selectors on sites like Digikey or Mouser to find an adequate hi-V PNP power transistor.

3 months, 2 weeks

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VCF Montréal 2026 Survey Results

by Jeffrey Brace

VCF Montréal 2026 Survey Results: English: https://bit.ly/vcfm2016post_results-en French: https://bit.ly/vcfm2016post_results-fr Jeff Brace VCF National Board Member Chairman & Vice President

3 months, 2 weeks

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VCF Montréal 2026 Survey

by Jeffrey Brace

VCF Montréal 2026 was a great success! Please fill out *one* of these anonymous surveys about the event: English: https://bit.ly/vcfm2026post-en VCF Montréal 2026 a été un franc succès ! Veuillez remplir *un* de ces sondages anonymes concernant l'événement : Français: https://bit.ly/vcfm2026post-fr Jeff Brace VCF National Board Member Chairman & Vice President

3 months, 3 weeks

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Gmail users appear to be disabled again

by Tom Hunter

Dear administrators, Once again Gmail users appear to have been disabled. Could you please help and re-enable me and others who have been affected. It is only 3 or 4 months ago when this happened last. It would be nice if this could be fixed permanently. Thanks and best regards Tom Hunter

3 months, 3 weeks

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Consignment active for VCF Montréal 2026

by Jeffrey Brace

VCF Montréal Consignment is active! Click below for more information. Le service de dépôt-vente VCF Montréal est opérationnel ! Cliquez ci-dessous pour plus d'informations. https://vcfed.org/vcf-montreal/vcf-montreal-consignment-consigne/#english

4 months

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Paper tape

by Adrian Godwin

I bought a reel of paper tape at an office supply shop today. It was in their 'bargains' room and is marked NCR SYSTEMEDIA 01-6388181 Telex 888634 PTI Made in England It cost me £0.50. I think they had two more reels. it's age is indicated by having a London phone number that was made obsolete 30 years ago. However, what surprises me is that it's 17.5 mm (0.69", 11/16") wide. This seems too narrow for 7-hole tape and too wide for the tape used for telegrams. Is it for 5-hole tape ?

4 months, 1 week

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ICON 3712 emulator?

by Joshua Rice

Hi all, I have a controller card (i'll elaborate later in the message) for an ICOM 3712 8" floppy drive unit. However, i do not have an FD3712 system to interface to it! With Shugart style floppy emulation essentially a solved problem, i'm wondering if similar has been done for the FD3712. As the computer side of the floppy interface is just a parallel interface, and all the disk geometry wizardry happens on the FD3712, i'd assume a lot of the difficulty of Shugart floppy emulation is essentially a moot point. So the question is, is there a project already existent to replace the FD3712 unit with an emulated (raspberry pi based?) alternative? I'm asking the question as i have an RCA Microboard bus CDP18S646 combined Centronics Printer interface and FD3712 floppy interface. It also came with an MBZ80 z80 based CPU card, and i'm putting 2 and 2 together and gathering it was likely the two were used together. If i've every got a a hope in hell of booting anything, solving the media problem is quite important. Cheers, Josh Rice

4 months, 1 week

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Anyone Have a VT100 and Able to Look at the Monitor Board?

by Rob Jarratt

As posted previously I am trying to repair my VT100 and I am having trouble with the Monitor Board. The one I have does not match the available printset (PDF p54 of this https://bitsavers.org/pdf/dec/terminal/vt100/MP00633_VT100_Schematic_Feb82.p df). My VT100 appears to match the older https://bitsavers.org/pdf/dec/terminal/vt100/MP00633_VT100_Mar80.pdf printset, but it doesn't cover the monitor board. My monitor board looks as follows https://rjarratt.wordpress.com/wp-content/uploads/2023/12/img_20231221_11223 3.jpg and the two big transistors on the left appear to be incorrect parts possibly from a previous repair attempt before I got the VT100. Does anyone have a previous revision of the VT100 with a Monitor Board that matches mine? If so, would you be able to photograph it please, or tell me what parts are installed for the two TO-3 transistors on the left? Better still would be if anyone has the printset for this version of the monitor board. Thanks Rob

4 months, 1 week

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Teletype 33 Available

by Martin Bishop

https://forum.vcfed.org/index.php?threads/teletype-33-southern-uk-trade-for… See VCF for info and pics Martin

4 months, 1 week

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C. Itoh CIT-220 keyboard options

by Alan Perry

I inherited a C. Itoh CIT-220 with no keyboard. Is the keyboard model- or C. Itoh-specific or will other keyboards work with it? alan

4 months, 1 week

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Ownership of microcomputing

by Murray McCullough

One of the greatest joys of classic computing was running what you wanted on your own computer. What has happened in the intervening years? Have ‘software walls’ created a computing environment that benefits software gate-keepers(owners of computing technology) by monopolizing creativity, freedom to program and establishing a defacto ‘true ownership’. Will the future be this or will it be more like the earliest years of microcomputing? Murray 🙂

4 months, 2 weeks

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VT180 boards

by Earl Baugh

I’ve recently come across 1/2 of an upgrade kit for the VT180 ( which upgrades it to a CP/M based machine — see : https://dunfield.classiccmp.org/dec/vt18x.pdf ). A friend around the same time rescued a floppy chassis which was also part of the upgrade. The problem is that we’re missing the PCB parts of the upgrade. This includes the VT180 paddle board, the VT18X Control board and maybe the VT100 expansion backplane. ( I haven’t opened up my VT100 to see what it has inside - I’ve only used it as a terminal ). ROM images are available and the partial kit I believe has all the standoffs, cables, badge, etc. Anybody know if anybody has made any reproduction PCBs for this upgrade? Or anybody know where I might find any of these parts? It would be fun to perform this upgrade and show it off at our next VCF-SE. Thanks in advance for any pointers. Earl Sent from my iPhone’s

4 months, 2 weeks

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VCF Midwest Hotel Rooming Open

by Jason T

...soon! Hotel room booking for the Vintage Computer Festival Midwest will open via the link on our site at 22:00 Central Time (that's about 20 minutes from now). Here is the link: https://vcfmw.org/hotel -jt

4 months, 2 weeks

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i8008 and interrupts

by Robert Armstrong

Can someone explain how the Intel 8008 (yes, the 8008, NOT the 8080!) handled saving and restoring the flags during an interrupt? The 8008 has four flag bits - CZS&P - but there doesn't seem to be any explicit equivalent to the PSW register nor any "PUSH PSW" or "POP PSW" type instructions. Other than testing the flag bits with the JUMP/CALL/RET instructions there doesn't seem to be any way to access them. Interrupts work pretty much like the 8080 - during the interrupt response the peripheral forces an instruction onto the bus, typically an RST opcode but in theory it could be anything. RST and CALL however only appear to save the PC on the internal stack, and RET only restores the PC. So how do you save and restore the flag bits? It seems like interrupts would be pretty much useless without this, so I must be missing something. Thanks,

4 months, 2 weeks

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RGS-008 replica

by brad

Hi there,I recently completed recreations of the Sol Intelligent Terminal and JOLT PCBs and have had a bunch produced if anyone is interested.But the real reason I am writing is I want to tackle a much more difficult project which is the RGS-008, which came out around the time of the Altair and was condemned obsolescence almost immediately following release.I am trying to track down any surviving copies of schematics or documentation. I have already reached out to CHM and a couple other folks but so far actual documentation remains elusive. CHM does have an RGS-008 based on the original wire wrap design, but no schematics.Probably these things are hard to find for a reason, but I thought I might reach out here to see if anyone has any other leads I could possibly follow. I suspect the basic design followed the reference design supplied by Intel, with some modifications. Many thanks and Happy New Year!BradSent from my Galaxy

4 months, 2 weeks

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IBM 2315 Cartridges

by Kurt Nowak

Hey all - I came across a big box of 12 of these disks which my dad acquired through work back in the 70s, and squirreled them away in the attic after they had copied the data. 4 of them have a broken metal access door. I opened one of the broken ones (in a clean of an environment as possible) to see what was going on inside. It looks like the door is held on by plastic divets that have broken off. They might be able to be repaired with small screws. I have no idea if these are functional or not. I am offering them up for free for anyone that can use them. I'm willing to ship or you pick up in San Diego. Here is a link to photos of them: https://drive.google.com/drive/folders/1wnzqjAtiq44MGU-wDJR-AQdzu-Mkyii8?us… -Kurt

4 months, 2 weeks

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Stewart Cheifet from The Computer Cronicles passed Dec 28th 2005

by Christian Liendo

https://obits.goldsteinsfuneral.com/stewart-cheifet He came to VCF East, this was his presentation https://youtu.be/Ncnje4DdRxE.

4 months, 3 weeks

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Re: Philips P2000C disk format

by Francis Massen

To use Greaseweazle with a 640kB drive (5.25, 80 track, DSDD) use the acorn.adfs.640 definition (diskdefs); it works like a charm ! More here: https://computarium.lcd.lu/literature/COMPUTARIUM_CREW/MASSEN/HANDLING_VINT… Francis PS: I am looking for a Kermit version usable with my P2000C (it is the 2010-1 model, very similar to the 2012); everything I tried until now did not work correctly...

4 months, 3 weeks

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Re: i8008 and interrupts

by trp

I didn’t see anyone post this clever way to save and restore flags in interrupt for the 8008. This is from https://stevemorse.org/8086history/8086history.pdf APPENDIX 1 SAVING AND RESTORING FLAGS IN THE 8008 Interrupt routines must leave all processor flags and registers unaltered so as not to contaminate the processing that was interrupted. This is most simply done by having the interrupt routine save all flags and registers on entry and restore them prior to exiting. The 8008, unlike its successors, has no instruction for directly saving or restoring flags. Thus 8008 interrupt routines that alter flags (practically every routine does) must conditionally test each flag to obtain its value and then save that value. Since there are no instructions for directly setting or clearing flags, the flag values must be restored by executing code that will put the flags in the saved state. The 8008 flags can be restored very efficiently if they are saved in the following format in a byte in memory. Most significant bit = bit 7 bit 7 = original value of CARRY bit 6 = original value of SIGN bit 5 = original value of SIGN bit 4 = 0 bit 3 = 0 bit 2 = complement of original value of ZERO bit 1 = complement of original value of ZERO bit 0 = complement of original value of PARITY With the information saved in the above format in a byte called FLAGS, the following two instructions will restore all the saved flag values: LDA FLAGS ;load saved flags into accumulator ADD A ;add the accumulator to itself This instruction sequence loads the saved flags into the accumulator and then doubles the value, thereby moving each bit one position to the left. This causes each flag to be set to its original value, for the following reasons: The original value of the CARRY flag, being in the leftmost bit, will be moved out of the accumulator and wind up in the CARRY flag. The original value of the SIGN flag, being in bit 6, will wind up in bit 7 and will become the sign of the result. The new value of the SIGN flag will reflect this sign. The complement of the original value of the PARITY flag will wind up in bit 1, and it alone will determine the parity of the result (all other bits in the result are paired up and have no net effect on parity). The new setting of the PARITY flag will be the complement of this bit (the flag denotes even parity) and therefore will take on the original value of the PARITY flag. Whenever the ZERO flag is 1, the SIGN flag must be 0 (zero is a positive two's- complement number) and the PARITY flag must be 1 (zero has even parity). Thus an original ZERO flag value of 1 will cause all bits of FLAGS, with the possible exception of bit 7, to be 0. After the ADD instruction is executed, all bits of the result will be 0 and the new value of the ZERO flag will therefore be 1. An original ZERO flag value of 0 will cause two bits in FLAGS to be 1 and will wind up in the result as well. The new value of the ZERO flag will therefore be 0. The above algorithm relies on the fact that flag values are always consistent, i.e., that the SIGN flag cannot be a 1 when the ZERO flag is a 1. This is always true in the 8008, since the flags come up in a consistent state whenever the processor is reset and flags can only be modified by instructions which always leave the flags in a consistent state. The 8080 and its derivatives allow the programmer to modify the flags in an arbitrary manner by popping a value of his choice off the stack and into the flags. Thus the above algorithm will not work on those processors. A code sequence for saving the flags in the required format is as follows: MVI A,0 ; move zero in accumulator JNC L1 ; jump if CARRY not set ORA 80H ; OR accumulator with 80 hex (set bit 7) L1: JZ L3 ; jump if ZERO set (and SIGN not set and PARITY set) ORA 06H ; OR accumulator with 06 hex (set bits 1 and 2) JM L2 ; jump if negative (SIGN set) ORA 60H ; OR accumulator with 60 hex (set bits 5 and 6) L2: JPE L3 ; jump if parity even (PARITY set) ORA 01H ; OR accumulator with 01 hex (set bit 0) L3: STA FLAGS ; store accumulator in FLAGS

4 months, 3 weeks

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Re: Hot Video Shift Register on VT100

by Rob Jarratt

I found some time to look at this again today. A few answers below. > -----Original Message----- > From: Martin Bishop <mjd.bishop(a)emeritus-solutions.com> > Sent: 30 November 2025 23:12 > To: rob(a)jarratt.me.uk; General Discussion: On-Topic and Off-Topic Posts > <cctalk(a)classiccmp.org> > Subject: RE: [cctalk] Re: Hot Video Shift Register on VT100 > > A short ground lead is 10 mm, from probe tip to ground spring see eg > https://www.aliexpress.com/item/1005007465068388.html > > However, ground springs require ground planes surrounding test points, or > test / ground point PEC layouts - very unlikely on a volume PCB. > > A 100 mm ground lead is neither short nor likely to be free of ringing. To > eliminate CRO probe ringing seriously short grounds are essential. > I pre-emptively bought an oscillator (24MHz and not 24.07342Mz) and tried it on a breadboard. This gave me the same signal with a negative spike on the falling edge. Although I don't have a ground spring I managed to shorten the ground connection considerably and this did indeed clear up the signal and it looked a lot squarer, without the negative spike. I lifted the original oscillator, but the leads on it are too short to work on my breadboard so I can't verify the same behaviour, but it seems highly likely that you are right that the negative spike is not real. That leaves me with the 74S299 still getting hot for reasons I don't understand. Maybe it is just the design, but the same chip in a VT102 doesn't get nearly so hot. Someone else suggested replacing it with a 74F299, so maybe I will try this now that I have socketed it. Regards Rob > Regarding some of the other points raised: > - 24.072 MHz is likely to be a magic number for video rates, with 24 MHz > YMMV > - the negative excursion may be clamped somewhere by diode(s) to gnd, > hence -1v2 .. - 1v4 excursion > - fast edges can be softened by a series resistor (22 .. 33 R say) following the > driver, triksy to retrofit > - are the power rails clean, on a scope, only pertinent if the spikes are > asynchronous to the signal(s) > > HtH; Martin >

4 months, 3 weeks

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Editing files in VMS over a telnet connection

by Peter Ekstrom

I feel like I have tried everything, although I'm sure I haven't... I have my real MV 3100 up and running with a serial terminal on the console port. It works great but I don't want to sit by the machine all the time to do stuff. I have DECnet running and am able to connect to it. I have an old raspberry pi running a minimal linux setup with the decnet stuff installed. So I ssh to the pi (named gatewy) and from there I use dnlogin to talk DECnet and connect to the machines. This way I can connect to my PDP-11 machines running RSX11M and M+ and use EDT to edit files in screen mode. When I try the same under VMS, EDT starts, loads the file and enters screen mode but just shows a blank screen with the cursor in the top-left corner. If I go to line mode I can walk through the file and edit using line mode. But as soon as I go back to the screen mode (the change command) I just get the blank screen. I have made sure TERM in each shell is vt100 and I have tried forcing VMS to VT100 but it stays with a vt200_series terminal. I also have a SIMH MV3100 also running VMS 5.3-1 (they both run on that version) and it acts the same way as the hardware MV3100. If I go onto the console connection in SIMH EDT works fine, as on the physical terminal on the real machine. Anyone have any pointers or ideas I can try? - Peter

4 months, 3 weeks

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Early delivery from Santa's sleigh

by Brian L. Stuart

So Santa had his sleigh out for some test drives tonight. For ballast (the real gifts won't be loaded until Wed night), he used a big stack of engineering drawings from the 1940s. Fortunately for us, his "spirited" driving included one turn that was too tight and out flew the drawings, where they landed on my lap. For anyone who's as eager as I am to geek out over 1940s computer design, I share them with you here: http://cs.drexel.edu/~bls96/eniac/drawings/ There are over 900 drawings in the set. Most of these images come from scans of microfilm taken of the patent trial exhibits. There are also about 100 copies that the Smithsonian had imaged and put up on their web site. I've processed them all to approximate something like we remember from our technical drawing classes in college (well those of us old enough to have taken them). The quality varies widely, but a large subset are readable down to the measurements for the panels and the component values in the circuits. If you've read Kathy Kleiman's excellent book (Proving Ground) about the original ENIAC programmers, you may have found yourself wondering what the block diagrams from which they figured out how to program the machine looked like. Well, those are among the drawings here. So feel free to try your hand at figuing out how to program it from them. One subset of the drawings is conspicuous by its absence, the PX-15 series. From what I can tell, those were drawings of a delay line memory unit that was never built. Those drawings were not part of the trial exhibits and were not microfilmed. However, some physical copies do exist, and I am hoping to get back into the archives to scan them at some point in the future. Beyond that, there are a number of drawing numbers that are skipped, and I suspect that these are drawings that do (or did) exist, but were not microfilmed for whatever reason. So if anyone has or comes across any drawings that are not on this list, or better copies of those that are, feel free to send scans my way. For anyone wanting to grab copies of the full set, it should be pretty easy to extract a file name list from the index.html file. I'll leave the sed command for extracting the list as an exercise for the reader. For printing, all of them are sized in the PDF files for 8.5x11 or 11x17 paper. Be warned, printing all of them without duplexing and folding the 11x17s to fit into a normal binder, ends up filling 2 4-inch binders. By the way, if anyone has access to the adapter shown in drawing PX-4-119, I think there's an error in the drawing and I'd like to check to see if either there really is or if I'm missing something. Thanks and have fun, BLS

4 months, 3 weeks

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DEC VT05 available in Germany

by hupfadekroua

Hi all, there is a DEC VT05 available in Germany. Please look at kleinanzeigen.de and search for DEC VT05. I already talked to the seller and he‘ll ship worldwide. Best

5 months

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Re: IBM 2315 Cartridges

by brian＠quarterbyte.com

> No. The only DEC drive that had removable plus fixed on the same spindle > was the RC25. > If I remember correctly it was Diablo that sold an RK05-compatible drive with one fixed platter and one removable cartridge. I encountered it on a PDP 11/34 running Mini Unix and then, hmmm, Unix v<something small>. (Or maybe had to move to a larger disk system when we moved up from Mini Unix. The details have gotten hazy.)

5 months

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Computer Collection Dissolution

by Jochen Kunz

Hello. So it is happening. Finally. What a relieve. I am giving away my (almost) entire classic computer collection. Free of charge (almost). But local pickup only due to health reasons. Read: Due to a physical disability I am not able to ship any computers. Location: Kaiserslautern, Germany. Almost because I will keep my beloved SPARCstation 1+, my SGI O2 and a few spare parts for sentimental reasons. I am still tempted to keep a QBus with a LSI11 and MicroVAX III... Anything else has to go. I don't wane make a profit out of it. I want the stuff go into good hands with absolut minimum effort at my side. As compensation I only ask for your help to get rid of some other stuff that has accumulated over the years. (Loads of disk, CDROM and tape drives. Cables, adapters, expansion cards, RAM modules, ... and some junk in my basement. More cables, 14" VGA monitor, glass-TTY, 19" rack mounts, empty boxes, ...) Either you take some of the junk with you, or you help me bring the junk to the nearby recycling center. I don't care, as long as the junk is gone. I may also request your help to rearrange existing or install new furniture in my appartement. (My desk uses the Sun 3/260 as support...) You want it all? Perfect. Rent a moving truck. Come and get it. You just want some pieces? Fine. Come, get what you want and take some junk out of the pile. The more nice stuff you take, the more junk you have to take. (Sounds worse then it is.) Almost complete list of stuff available below. Almost all stuff can be picked up and transported by a singe, strong person. Only a few pieces will require an additional hand, that I can not provide my self due to health reasons. Contact me off list with your machines of interest to get things arranged. Rationale: I haven't done anything with this stuff in 15+ years. After 15 years, I am quite confident that this will not change. I tried to get back into it in 2010 by acquiring a PDP-11/34A. After a few weeks I lost interest and now it is sitting partly disassembled and waiting for repairs. (The PSU bricks need new electrolytic capacitors...) Sitting there for 15 years. Untouched. I haven't really read any postings to this list in 10+ years. I am basically only still subscribed to nag myself to write this email. For me, my machinery is like books that I have read. I had a lot of fun reading those books. I learned a lot out of them. Most important are the people that I got to meet via them. Like this very mailing list and the legendary VAXpower meetings... :-) But now I know all the books. There is nothing new to discover. The books just sit there on shelves, collecting dust. It reached a point where all this stuff is getting in my way to live a happy live. The collection has become an obligation, a burden. Especially as: At the end of 2009 my back broke and I needed an emergency surgery. Now I have to be very careful with lifting and carrying stuff. I don't move anything over maybe 6 kg anymore. (That is 13ish pounds for you imperialists. ;-) ) This is also the reason why I can not ship anything. I am simply not physically able to package the stuff and bring it to the post office without risking breaking my back again. And when my back brakes again, I may end up in a wheelchair. I escaped that just barely when my back broke initially in 2009... Needless to say that this physical damage also caused mental issues. I will not take any risk breaking my body again. Also: I live in an old appartement building. My landlord will renovate the appartement that I rent in late summer 2026. I may move out of this appartement into an other one in spring 2026, so that the appartement is uninhabited during renovation. I will not move all of this stuff to a new appartement. And if I don't move, I wane get rid of the collection anyway. It will ease the renovation process a lot. Anything that is not already gone when the renovation starts, respectively on moving day, will be recycled. If this means the PDP-11/34A goes into the dumpster to be shredded, than it will happen. Machinery: DEC PDP-11/34A + RK05, optionally in low boy 19" rack. Shares a RL02 and a Cypher 9-track Pertec tape drive with the 11/73. Tektronix 4000-something storage tube vector graphics terminal. I think I still have the accompanying Tek printer. Originally part of the 11/34A system. DEC PDP-11/73, the "franken-11" I pieced this together over time in a BA23 desk side box. Runs 2.11BSD. Has 4 MB RAM, 2 x MSCP ESDI disks (IIRC 150 MB each), TK50, RL02, SMD and Pertec adapters. Comes with a 9" 1 GB E-SMD disk. Shares a RL02 and a Cypher 9-track Pertec tape drive with the 11/34A. DEC VAX 4000-300, upgraded to a -400 DEC VAX 4000-200 DEC VT1300 2 x DEC VAXstation 2000 (At least one has patched ROMs to boot SCSI.) DEC VAXstation 3100m76 DEC VAXstation 4000 VLC DEC VAXstation 4000-60 DEC VAXstation 4000-90 DEC MicroVAX 3100-95 DEC DECstation 3100 DEC DECstation 5000-240 DEC AlphaStation 200 4/166 DEC 3000 300x DEC 3000 600 DEC Alpha PWS 500au DEC Alpha DS20E (I don't know for sure. It has no model number on the front. It looks like a DS20E. I have never, ever even powered up this thing.) Tektronix 8560 Multi-User Software Development Unit This is a DEC PDP-11/23 CPU in Tek box. It runs a customized UNIX V7. At my parents place there should still be MicroVAX III MicroVAX 3500. 2 x 9" NEC E-SMD disks, 1 GB Tektronix 4000-something text terminal with storage tube. Additional logistics will be required if you wane retrieve this stuff. IBM PS/2 Modell 95 XP 486 IBM PS/2 80 IBM RS/6000 43P-140 IBM RS/6000 43P-150 IBM RS/6000 44P-170 SGI Indy SGI Octane, SSE GFX, PCI card cage with SCSI and FDDI cards. IIRC 300 MHz R12k and 2 GB RAM. There must be an additional SI or SE graphics somewhere. I run this machine dual headed. This was my main desktop from 2001 to 2006. SGI Personal IRIS, probably a 4D/25, I can't remember. SGI Indigo IIRC R3000 SGI Indigo IIRC R4000 SGI Indigo 2 teal R4000, Extreme GFX SGI Indigo 2 magenta R10k, Impact GFX SGI Octane carcass (Empty main box with front plane, no CPU, GFX, ...) SGI Origin 200 Sun 3/60 Sun 3/60 box with Sun 4/600 board inside, -12V hack for console RS232. Sun 4/110 Sun 3/260 Sun SPARCstation IPX Sun SPARCstation 2 Sun SPARCstation 5 Sun SPARCstation 10 Sun SPARCstation 20 Sun Ultra 1 creator3D Sun Ultra 2 Sun Ultra 5 ("franken 5" build from parts into a PC box.) Sun Ultra 10 Sun Netra X1 Sun Netra T1 Sun Fire V240 Apple Macintosh IIci Apple MacMini G4 Apple PowerMac G5, single 1,8 Ghz. Motorola MVME Type 3200, desktop box, 4 x 6U VME, IIRC MVME162 CPU. Sony NEWS NWS-3410 HP Apollo 400 425t HP 9000 750 (It may be 400s, but IIRC it is a 750.) HP 9000 B2000 Loads of (mostly SCSI) disk, CDROM and tape drives. Cables, adapters, expansion cards, RAM modules, hubs, switches, FDDI concentrator, ... IBM P200 / Sony Trinitron 19" monitor. Does sync on green. I used it with my SGIs. HP LaserJet 4 with JetDirect LAN (The VF-Display is dead, but otherwise works.) 2 x HP Scanjet IIc, one has an Automated Document Feeder. Works great with Impresario from SGI IRIX. Test equipment: Dolch Logic Instruments logic analyzer. IIRC 48 channels @ 300 MHz. HP Digital Storage Oscilloscope 54710 with 3 x 1 GHz / 2 Msamels/s Y-modules. Analog photo gear: Durst Laborator 1000 4"x5" enlarger, table top version. -- tschüss, Jochen

5 months

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Beginning January 2026, all ACM publications and related artifacts in the ACM Digital Library will be made open access.

by Christian Liendo

Dear Members of the Computing Community, We are pleased to share an important milestone for our field. Beginning January 2026, all ACM publications and related artifacts in the ACM Digital Library will be made open access. This change reflects the long-standing and growing call across the global computing community for research to be more accessible, more discoverable, and more reusable. https://dl.acm.org/openaccess

5 months

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[OT] Digikey's project of the week is impressive

by me＠scifidan.com

A dude decided to do a hackodore 64 laptop in the most expensive way possible, but it's a beautiful result. Nice design ethic. I don't typically share youtube links but this one is a nice exception. https://www.youtube.com/embed/H5QQ0ECfwyE I hope this inspires perifractic into doing a c128 laptop after their new fpga64 ships. Daniel sysop | Air & Wave BBS finger | calcmandan(a)bbs.erb.pw

5 months

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Re: Computer Collection Dissolution

by george.batsilas＠bluewin.ch

Hi Jochen I am an SGI collector from CH and am interested in any SGI and also other systems that you can spare. How can I get in touch with you to arrange a pickup in Kaiserslautern? tschüss George

5 months

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VCF Montréal 2026 Tickets on Sale!

by Jeffrey Brace

Les billets pour le VCF Montréal sont en vente dès maintenant! / VCF Montreal tickets on sale now! https://events.humanitix.com/vcfmontreal2026?c=cctalk More info: https://vcfed.org/vcf-montreal/ Jeff Brace

5 months

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Re: VAX and OpenVMS

by Peter Ekstrom

Just to tie a knot on this.... The MV 3100 is working great. I did replace the RZ25 drive with a ZuluSCSI and have it emulating a couple of RZ25s. I have VMS 5.3-1 up and running. I used the licenses from the OS that was running on it. I also have it on my DECnet network with my PDPs. The PSU looks great and the battery is not a problem either. The CDROM drive I got works great in an old Sun 411 enclosure attached to SCSI-B. I haven't used the TZ30 tape drive yet. I am going to see if I can treat the tapes I have to some time in the dryer and see if that helps. I think the surface of the tapes has softened and is leaving residue on the r/w head. I have read of some folks having success with the dryer. We shall see. But for now I am quite happy with it. Thank you everyone for all help and advice! - Peter On Mon, Dec 1, 2025 at 10:30 AM emanuel stiebler <emu(a)e-bbes.com> wrote: > On 2025-11-30 14:53, Peter Ekstrom via cctalk wrote: > > Very interesting thread. I was kinda thinking too that someone running > VMS > > on a machine for hobby use would be too small of a potato to go after. > > Incidentally, what would y'all value a MicroVAX 3100 at? I am looking at > > one on eBay for $550 but am considering making a lower offer. > > Which 3100? > There are some very low performance 3100 at the lower end, and the > best(?) 3100/105 or 3100/95 still fetch some serious money. > > My recommendation is usually the pizza box 4000/vlc ... > Specially, if you don't know what you need it for :) > >

5 months, 1 week

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Requesting advice on my restoration

by me＠scifidan.com

I want to prep the outer shell of my new tandy model 102 for paint and wish to remove the beautiful metal badgee from its recessed holder. I considered using a heat gun but fear it may effect the plastic casing around the badge. Last thing I want to do is damage the badge. Any clues? Daniel sysop | Air & Wave BBS finger | calcmandan(a)bbs.erb.pw

5 months, 1 week

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CNC with pdp 11 minicomputers

by devin davison

It's been a while since i last wrote to the list. I have been reading up a lot on early cnc systems. While recently picking up some left over tech from a shutdown machine shop, spotted a early cnc system with some kind of minicomputer attached. Looked to have some kind of tape drive and paper tape punch. It looked like it was stored under a leaky roof, ball of rust, it looked too far gone to salvage anything useful. Sadly phone was dead at the time and i did not get pictures. Reading up on wikipedia, Data General Nova and Dec PDP 11 mini computers are mentioned as used in early cnc. Are there any surviving cnc systems, details, or software for the pdp 11? I am interested to know a bit more how the hardware was interfaced. I have pdp 11/34 systems for example, not sure if the external machine hardware is directly wired into the unibus with a/d cards, or if some kind of external hardware controller is driven by the pdp. I have not found much info on any software used for this purpose. Any accounts of how this worked or other interesting stories / info much appriciated. Thanks, Devin D'Amico

5 months, 1 week

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STD Bus based Little Big Board

by Doug Jackson

Hi Everybody, I am on the search for a Pulsar Electronics Little Big Board (STD Bus Based) from the mid 80's. My board has some very weird bus faults that I am trying to diagnose. Having a working one would radically simplify my life. I am located in Canberra, Australia, and am happy to pay for the board and postage from Alaska if necessary :-) Kindest regards, Doug Jackson em: doug(a)doughq.com ph: 0414 986878

5 months, 1 week

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Re: IBM 2315 Cartridges (Paul Koning)

by Carl Claunch

I am interested in reading these and archiving the contents. I restore IBM 1130 systems and am archiving software to be shared with enthusiasts and museums. Located in Florida so shipping would be necessary. Might need to be creative to keep the cost of shipping reasonable. The cartridges are not sealed, thus you can open them without a clean room. The plastic hardens over the decades and it is not uncommon to have the springy metal plate detach. It would be important to get the detached ones out of the cartridge otherwise they could scratch the recording surface and ruin the disk. These have eight sector marks per rotation although the IBM 1130 hardware skips every other mark to use these as a four sector disk. Carl

5 months, 1 week

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1989 286 "luggable" by Fontex Technology Group, Prolite 206/16-047

by Martin

Hi all, My apologies if this is not the kind of "classic" computer people are interested in but I have a Fontex Technology Group Prolite 206/16-047. It is in good physical condition with the original case, mouse and manual. It powers on but I don't have suitable disks so I can't get it to boot. I can send photos of it if that's of use. I'm trying to find it a new home rather than scrapping it. Is anyone interested? It's currently in London and I would suggest collection because it is not light but if there is someone who wants it shipped and is willing to pay then I will give it a go! Cheers, - Martin

5 months, 1 week

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TRS-80 Tiny Pascal

by Bill Gunshannon

Back in the day I did a lot of playing around with the Radio Shack versions of Tiny Pascal. (Back in the days when you loaded them from tape cause we didn't have disks yet!) I still like to mess with Tiny Pascal on other machines, too. Now the bad news (at least for me). While I have my Model I version tape I cannot find the tape for the Model III. Does anyone have a copy of the tape or an image of the tape usable on an emulator (pretty sure I can put that back onto a tape.) I would really like to get back to trying some things with it. bill

5 months, 1 week

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Re: IBM 2315 Cartridges

by junk myalternateemail.com

Aarrgh. Have you no respect for your cars paint job? :)

5 months, 1 week

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MicroVAX 3100 ( was: Re: Re: VAX and OpenVMS)

by Peter Ekstrom

Alright, so the 3100 arrived yesterday afternoon and looks to be in good condition visually. The voltages from the PSU look ok as well. So I plugged things back in and powered it on. I don't have a console for it yet, but it seems to go through some self-test, the tape drive does some stuff as well as the hard drive. It came with the slightly larger RZ25 rather than the RZ23. I am getting some 6-conductor cable soon and will make a console cable for it. I'm very curious to see what it does on the console. I have a SCSI CDROM coming in a few days. I also have an old SUN external enclosure that I'll put to use for it as an external CDROM. Interestingly, it doesn't have a model number on the sticker, but based on what I have seen, and the pattern of the connectors in the back, I am pretty sure it is a model 10. - Peter On Mon, Dec 1, 2025 at 10:30 AM emanuel stiebler <emu(a)e-bbes.com> wrote: > On 2025-11-30 14:53, Peter Ekstrom via cctalk wrote: > > Very interesting thread. I was kinda thinking too that someone running > VMS > > on a machine for hobby use would be too small of a potato to go after. > > Incidentally, what would y'all value a MicroVAX 3100 at? I am looking at > > one on eBay for $550 but am considering making a lower offer. > > Which 3100? > There are some very low performance 3100 at the lower end, and the > best(?) 3100/105 or 3100/95 still fetch some serious money. > > My recommendation is usually the pizza box 4000/vlc ... > Specially, if you don't know what you need it for :) > >

5 months, 1 week

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Rockwell PPS-4 documents needed. MM7X stuff

by John Robertson

Hi Folks, I've done the online searches, and know that bitsavers.org (Hi Al !) has a reasonable amount of information, however I am looking for ap notes and more information than is currently archived. At the moment one chip I am researching is the MM76E (not the 40-pin EL version) ROM as I can't find the pinout anywhere - so far. I can figure it out, but it is always better to have the manual if possible... Any documents found will be off to bitsavers of course, but I'm hoping that someone here has an ancient (70s!) Rockwell manual on these 42-pin spider chips! Did anyone ever make an emulator for the MM78 CPU family? Thanks, John :-#)# Also posted to s.e.design as one never knows with usenet what turns up... -- John's Jukes Ltd. 7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 Call (604)872-5757 (Pinballs, Jukes, Video Games) flippers.com "Old pinballers never die, they just flip out"

5 months, 2 weeks

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Re: Information on the PPS-4/1 4 bit microprocessor wanted - MM76E (not MM76EL)

by John Robertson

Resurrecting a very old (2011) thread about PPS-4/1 - I'm looking for data sheet on the mm76E - the pinout in particular - as I am trying to sketch out the schematic of a home pinball game that used the MM78 CPU and the MM76E for memory. Bitsavers and everyone else has the sheet for the MM76EL which is the 40-pin version of the original spider chip and those pages talk about how the EL does not require as fussy a voltage for Vss. Anyway, if anyone has this data I'd appreciate it! Thanks, John :-#)# On 2011-10-31 1:29 a.m., Eric Smith wrote: > Benjamin Sølberg wrote: > > So if you multiplex 8 leds you need 8 times the peak current to keep > the > > same luminance ? > > 8:1 multiplex requires 8 times the peak current to get the same > average power. Years ago I saw some claims that with multiplexing you > can use lower average power for the same perceptual brightness, due to > retinal persistence. However, I've seen other people claim that this > is not true. It would be entertaining to set up a double-blind test > and find out.

5 months, 2 weeks

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Re: who has a computer of your very own

by Tom Stepleton

> > Too late now, but those keyboards were actually standard Keytronics > ones, and not at all hard to repair. > > -tony > I'm fairly certain that the MG-1 I have is one of the Stern Hall machines mentioned earlier. But in re "standard Key Tronic"... The one here is certainly a foam-and-foil capacitive device like a Key Tronic keyboard is, and surely the mechanism is basically identical (as are its repair methods). It still works --- for now. But the pads aren't little round tablets like the usual KT fare but instead squares with one of the corners notched out (think: the shape of Utah, but squarer). I do not look forward to those pads degrading further and expect it may be necessary to get some kind of custom die punch fabricated in order to produce replacements. I can't easily retrieve the name of the keyboard manufacturer at the moment, but I wonder if anyone knows more about this odd shape of capacitive pad. --T >

5 months, 2 weeks

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IBM SP?

by Ben Huntsman

Hi there! Long shot here, I know, but does anyone on here have an IBM SP node, especially an earlier (non Power 3) Thin Node with MCA? But really any SP owners here at all? Thanks!! -Ben

5 months, 2 weeks

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Classic computing - earliest years

by Murray McCullough

Hi everyone, According to historians, and I consider myself one, let us consider what classic/vintage computers were: The 1970s saw the three amigos: Apple II, TRS-80 and Commodore PET and the OS was DOS and its ilk + CP/M. The 1980’s saw the Dells, HPs and many others with MS-DOS & IBM PC-DOS from QDOS. We saw this and behold ’bring on the clones’(I just had to say this!) The era of old computers saw one generation building on the shoulders of giants who designed these wayback computers(with apologies to Wayback Machine). Today’s PCs and ARM machines are just the latest iteration of this theory(by the way not mine). Happy computing Murray 🙂

5 months, 2 weeks

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OCR and line printers

by Guy Fedorkow

Greetings Restorers, I think a number of us have wanted to restore software that's only available as a scanned listing from a line printer. The original printout probably wasn't the best typographic quality, and scanning doesn't improve it. As a first pass, OCR with tools like Adobe Acrobat can easily produce a rough draft of the content in text form, but it takes almost as much work to correct the many "typos" as it does to simply re-type the listing. It seems like, with all this high-tech AI processing around, it should be possible to take advantage of the limited character set, fixed fonts, and restricted grammar that one might find in a listing to resolve more of the ambiguities in character recognition. Does anyone have an approach that's more efficient than generic OCR and a long process of correcting typos on every line of code or comment? Thanks /guy

5 months, 2 weeks

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Friden Flexowriter models

by Peter Brown

I have recently acquired a Flexowriter. It looks very much like the one shown on this page - https://moca.ncl.ac.uk/iomedia/pt4.htm The identifying points are - blue color keys - tape punch and reader (both appear to be 8 bits) - white and red lamps on the front panel beneath the Friden logo The serial number plate shows F_V as the model and S P E C as the coding. Is anyone familiar with what this model is? What does the coding refer to? Peter

5 months, 2 weeks

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Need a Connectix camera?

by Van Snyder

I have a Connectix camera with a small 8-pin mini-DIN connector. The pin placement looks like RS-232. All it says on the label is that the FCC id is LKD1. The only thing I found about it online called its a Macintosh camera. Logitech bought the Quick Cam from Connectix in 1998 but I can't find much more about it, or even if it's the one with FFF id LKD1. Do you want it?

5 months, 2 weeks

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Re: Conductive material in rubber dome

by Teo Zenios

With all the talk going on, I ordered some ButtonWorx 4mm keypad repair buttons to fix my old Technics stereo rubber dome remote and it seems to work good as new. Now I just have to replace some capacitors in the receiver itself. -----------------------------------------From: "Daniel L via cctalk" To: "General Discussion: On-Topic and Off-Topic Posts" Cc: "Daniel L" Sent: Sunday November 30 2025 5:40:55AM Subject: [cctalk] Re: Conductive material in rubber dome Well folks, it was a false alarm. My wife was looking at my open switches and told me to zoom in with my camera. It turned out that it wasn't the dome itself. The dome had left just enough residue on the switch contacts to prevent consistent usage. So I sprayed excess contact cleaner and a qtip and cleaned it vigorously. Voila, all three switches work perfectly. It took a better part of five hours to do all of them. I figure this would likely happen again. And I was concerned the self adhesive version would break off during use but, no. The material in the domes is self adhesive. The dome material was also cast to be quite flat. I didn't have to use any of the new bits since it's still in shipping from amazon. But, I have them in stock because there are a number of 100s I will be refurbishing for resale at some point. I'm glad the wife looked at it with her eagle eyes. I would've torn off the original stuff and it wouldn't have worked. I would have kicked myself. I also replaced the leaky battery on the mobo so she's ready for modifications! Looking forward for this project. Daniel sysop Air & Wave BBS finger calcmandan(a)bbs.erb.pw On November 26, 2025 5:04:11 AM PST, me--- via cctalk wrote: >I just acquired a TRS-80 model 102, my first of that model. > >Everything is great other than three keys. The 2 keys works intermittently, q, and [ don't work. Having checked the schematic, the keys have no commonality on the circuit. > >Before I pull the cap off the switch, I know that the rubber dome inside has material on the inner part that meets with the silver contacts to complete the circuit. I'm told this material will wear out or lose conductivity. > >I reflowed the solder joints on the pcb and this didn't help. Other people have simply replaced the rubber dome from another dead 102's keyboard. But, I'd rather attempt applying new material inside that dome. > >I'm hoping there is an inexpensive and mainstream solution I can buy at home depot or something. > >Any tips? > >Daniel >sysop | Air & Wave BBS >finger | calcmandan(a)bbs.erb.pw

5 months, 2 weeks

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DECnet 5.4 install media

by Peter Ekstrom

I am playing around with VMS 5.4 on a simulated microvax 3100 and want to get decnet running. The install media I have found is for decnet 4.0 end-node but it doesn't install. Vmsinstal complains about symbols not being defined and I am guessing I have the wrong version for VMS 5.4. Does anyone know of a decnet version that will work on VMS 5.4? I can't seem to find one. Thanks, - Peter

5 months, 2 weeks

8
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Brainless Message Quoting

by Marvin Johnston

Rob, What is behind this stupidity of quoting the entire listserver replies (well, it seems like it anyway) on your messages????? Quoted below is what I am talking about. Maybe it is past time for you to learn about editing! Marvin > Message: 11 > Date: Sun, 30 Nov 2025 12:56:45 -0000 > From: "Rob Jarratt"<robert.jarratt(a)ntlworld.com> > Subject: [cctalk] Re: Hot Video Shift Register on VT100 > To: "'General Discussion: On-Topic and Off-Topic Posts'" > <cctalk(a)classiccmp.org> > Cc: 'Hans-Ulrich Hölscher'<vaxorcist(a)googlemail.com> > Message-ID:<013e01dc61f8$c8d2e3c0$5a78ab40$(a)ntlworld.com> > Content-Type: text/plain; charset="iso-8859-1" > >> -----Original Message----- >> From: Hans-Ulrich Hölscher via cctalk<cctalk(a)classiccmp.org> >> Sent: 29 November 2025 09:17 >> To: General Discussion: On-Topic and Off-Topic Posts > <cctalk(a)classiccmp.org> >> Cc: Hans-Ulrich Hölscher<vaxorcist(a)googlemail.com> >> Subject: [cctalk] Re: Hot Video Shift Register on VT100 >> >> Hi Rob, >> this is not intended to indicate the cause or solution, but merely to help >> analyze how critical your IC temperature is: Did you actually measure the >> temperature of the IC? I recently bought an inexpensive infrared >> thermometer (like:https://www.ebay.co.uk/itm/156810933790) that can >> measure the temperature of small areas relatively accurately. I made the >> experience that I cannot judge temperatures very well with my fingers. >> >> According to Wikipedia, TTL ICs are specified for temperatures up to >> 70 °C. This >> temperature should obviously be avoided, but my fingers already perceive >> anything above about 50 °C as "hot". >> >> I hope this can help a litte! > Yes, I have an IR Thermometer and the chip gets to about 40 celsius. I > realise that this is well below the maximum rating, but I can smell the heat > and it worries me a bit. If I knew this was expected then I would be OK with > it, but it feels anomalous and I have felt the chip to be hotter than this > sometimes. The observation about the negative voltages also concerns me a > bit, although I do have spares for the 74S299 should I need them. > > It looks now like the DC011 is just producing a DOT CLK output with negative > spikes. Maybe this is why later revisions introduced an inductor or maybe it > is just a bad DC011 or something is wrong with what is around the DC011. > > I am going to look at the DC011 inputs to see if anything looks amiss. The > other thing I would like to do is to see what happens if I can add an > inductor to the output of the DC011. But I don't know how to read the spec > on the printset to know what I might need. The printset says "BEAD, FERRITE > .1380DX.380LG", can anyone tell me what this might mean in terms of an > inductor that I could try? > > Thanks > > Rob > > >> Ulli >> >> Am Sa., 29. Nov. 2025 um 09:44 Uhr schrieb Henk Gooijen via cctalk < >> cctalk(a)classiccmp.org>: >> >>> Rob, >>> >>> I have a few silly thoughts, but maybe they can be useful. >>> The negative going signal is something I would not be happy with, as >>> it may damage the IC (over time). >>> TTL does not like negative voltages on their pins. >>> Is there between the DC011 (signal generating) and the LS299 (signal >>> "user") wiring, or are they on the same PCB? >>> In case of wiring, capacitive coupling may cause negative going > voltages. >>> Could a clamping diode with an as low as possible Vf (< 0.3 V) help to >>> reduce the negative voltage? It is not a permanent solution, because >>> the >>> DC011 might be a bit unhappy with that diode, but for a test it might >>> help to draw a conclusion. >>> >>> If all does not help, in getting the LS299 running cooler, consider >>> some temperature conductive paste and a small "IC heatsink". Tie the >>> heatsink onto the IC with a piece of waxed lacing. The IC can radiate >>> more efficiently the generated heat, so that it can run cooler. This >>> could drop temperature with some 10 degrees. >>> >>> Success hunting down this issue, >>> Henk >>> >>> -----Oorspronkelijk bericht----- >>> Van: Rob Jarratt via cctalk<cctalk(a)classiccmp.org> >>> Verzonden: zaterdag 29 november 2025 08:11 >>> Aan: 'Doug Jackson'<doug(a)doughq.com>;rob(a)jarratt.me.uk >>> CC: 'General Discussion: On-Topic and Off-Topic Posts' < >>> cctalk(a)classiccmp.org>; Rob Jarratt <robert.jarratt(a)ntlworld.com> >>> Onderwerp: [cctalk] Re: Hot Video Shift Register on VT100 >>> >>> Yes, it is a negative voltage. I measured this by attaching the ground >>> lead to the ground connection on the 74S299. >>> >>> >>> >>> The DC011 that is producing the CLK signal is socketed, but the one on >>> my >>> VT102 isnt. I would try swapping them to see what happens, but I >>> dont really want to touch a fully working board. >>> >>> >>> >>> Thanks >>> >>> >>> >>> Rob >>> >>> >>> >>> From: Doug Jackson<doug(a)doughq.com> >>> Sent: 28 November 2025 22:59 >>> To:rob@jarratt.me.uk >>> Cc: General Discussion: On-Topic and Off-Topic Posts < >>> cctalk(a)classiccmp.org> >>> Subject: Re: [cctalk] Re: Hot Video Shift Register on VT100 >>> >>> >>> >>> Is that a negative excursion at the bottom of the waveform? now low - >>> looks like -0.3v to me - With '"logic, that will likely turn on the >>> protection diodes on the inputs, making them warm. >>> >>> >>> >>> Double check where the ground actually is on the CRO display. >>> >>> >>> >>> It's also interesting that the input doesn't even reach 4v, let alone > 5v. >>> Whats driving that? >>> >>> >>> >>> >>> >>> Kindest regards, >>> >>> >>> >>> Doug Jackson >>> >>> >>> >>> em:doug@doughq.com <mailto:doug@doughq.com> >>> >>> ph: 0414 986878 >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> On Sat, 29 Nov 2025 at 08:52, Rob Jarratt <robert.jarratt(a)ntlworld.com >>> <mailto:robert.jarratt@ntlworld.com> > wrote: >>> >>> I checked the CLK input for the 74S299 with the 74S299 removed and the >>> signal is still spiky and looks like this: >>> https://rjarratt.wordpress.com/wp-content/uploads/2025/11/vt102-74s299 >>> -clk-signal.png >>> >>> >>> >>> I removed the other load on this signal, the DC012, and the CLK signal >>> still looked spiky. I also put back the 74S299 (now socketed) with >>> DC012 removed and it still gets hot. I tried another new 74S299 just >>> in case I had a bad one and that also got hot without a load on the > output. >>> >>> >>> I am thinking that it is either the spiky input or it is just expected >>> to get this hot. >>> >>> >>> >>> Regards >>> >>> >>> >>> Rob >>> >>> >>> >>> From: Doug Jackson <doug(a)doughq.com <mailto:doug@doughq.com> > >>> Sent: 25 November 2025 01:15 >>> To:rob@jarratt.me.uk <mailto:rob@jarratt.me.uk> >>> Cc: General Discussion: On-Topic and Off-Topic Posts < >>> cctalk(a)classiccmp.org <mailto:cctalk@classiccmp.org> > >>> Subject: Re: [cctalk] Re: Hot Video Shift Register on VT100 >>> >>> >>> >>> The oscilloscope will show you the actual driving waveform. >>> >>> >>> >>> You can then see the level of the spikes >>> >>> >>> >>> Kindest regards, >>> >>> >>> >>> Doug Jackson >>> >>> >>> >>> em:doug@doughq.com <mailto:doug@doughq.com> >>> >>> ph: 0414 986878 >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> On Tue, 25 Nov 2025 at 10:48, Rob Jarratt <robert.jarratt(a)ntlworld.com >>> <mailto:robert.jarratt@ntlworld.com> > wrote: >>> >>> >>> >>>> -----Original Message----- >>>> From: Doug Jackson via cctalk <cctalk(a)classiccmp.org <mailto: >>> cctalk(a)classiccmp.org> > >>>> Sent: 24 November 2025 23:04 >>>> To: General Discussion: On-Topic and Off-Topic Posts < >>> cctalk(a)classiccmp.org <mailto:cctalk@classiccmp.org> > >>>> Cc: Doug Jackson <doug(a)doughq.com <mailto:doug@doughq.com> > >>>> Subject: [cctalk] Re: Hot Video Shift Register on VT100 >>>> >>>> Another test would be to disconnect the output and see if that runs >>>> the device cooler. Maybe the load, while not a short, is simply too >>>> great >>> for the >>>> device. >>> I think I can try this, the DC012 it drives is socketed. >>> >>>> But I am leaning towards the inputs containing spikes that need to >>>> be dissipated as heat in clamping diodes. A decent CRO on the >>>> device input >>> pins >>>> while it is out of circuit will show that as well. >>> I guess CRO means Cathode Ray Oscilloscope? Not sure what you are >>> suggesting I try here? >>> >>> >>>> Kindest regards, >>>> >>>> Doug Jackson >>>> >>>> em:doug@doughq.com <mailto:doug@doughq.com> >>>> ph: 0414 986878 >>>> >>>> >>>> >>>> >>>> On Tue, 25 Nov 2025 at 09:52, Peter Coghlan via cctalk < >>>> cctalk(a)classiccmp.org <mailto:cctalk@classiccmp.org> > wrote: >>>> >>>>>> Sorry if I wasn't clear in my earlier reply, but there were some >>>>>> answers inline. The summary is that Vcc looks fine, there does >>>>>> not seem to be any short on the outputs of the shift register >>>>>> and the chip seems to be >>>>> working >>>>>> correctly. It just gets hot and I wonder if this could be due to >>>>>> the CLK input being a bit spikier on the VT100 than on my VT102? >>>>>> Could this be >>>>> why >>>>>> later revisions of the VT100 introduced an inductor on the DOT >>>>>> CLK output from the DC011? >>>>>> >>>>> Perhaps one way to test the hypothesis would be to insert an >>>>> inductor like those used on the later revisions in the DOT CLK >>>>> output and check whether >>>>> a) everything still works and b) the shift register runs cooler? >>>>> >>>>> Regards, >>>>> Peter Coghlan. >>>>> >>> > > ------------------------------ > > Message: 12 > Date: Sun, 30 Nov 2025 14:30:54 -0000 > From: "Rob Jarratt"<robert.jarratt(a)ntlworld.com> > Subject: [cctalk] Re: Hot Video Shift Register on VT100 > To:<rob(a)jarratt.me.uk>, "'General Discussion: On-Topic and > Off-Topic Posts'"<cctalk(a)classiccmp.org> > Cc: 'Hans-Ulrich Hölscher'<vaxorcist(a)googlemail.com> > Message-ID:<014901dc6205$efd87090$cf8951b0$(a)ntlworld.com> > Content-Type: text/plain; charset="iso-8859-1" > > I have traced the clock signal back. The MAS CLK input on the DC011 also has > the negative spikes. This is coming from a 74S157. The input to that is an > oscillator and that too has the negative spikes. > > So, it seems the 74S157 is just passing through the inputs. > > There is a capacitor across pins 4 and 2 of the oscillator (Vcc and Gnd), > would a failure there cause this kind of negative spike? It seems unlikely > to me, but would be happy to be corrected. > > The oscillator is rated at 24.0734MHz. I can find lots rated at exactly > 24MHz and I guess the difference in frequency is small enough not to matter, > right? > > I will order the part and also a new capacitor for it in case that is where > the fault lies and see. > > Thanks > > Rob > > >> -----Original Message----- >> From: Rob Jarratt via cctalk<cctalk(a)classiccmp.org> >> Sent: 30 November 2025 12:57 >> To: 'General Discussion: On-Topic and Off-Topic Posts' >> <cctalk(a)classiccmp.org> >> Cc: 'Hans-Ulrich Hölscher'<vaxorcist(a)googlemail.com>; Rob Jarratt >> <robert.jarratt(a)ntlworld.com> >> Subject: [cctalk] Re: Hot Video Shift Register on VT100 >> >>> -----Original Message----- >>> From: Hans-Ulrich Hölscher via cctalk<cctalk(a)classiccmp.org> >>> Sent: 29 November 2025 09:17 >>> To: General Discussion: On-Topic and Off-Topic Posts >> <cctalk(a)classiccmp.org> >>> Cc: Hans-Ulrich Hölscher<vaxorcist(a)googlemail.com> >>> Subject: [cctalk] Re: Hot Video Shift Register on VT100 >>> >>> Hi Rob, >>> this is not intended to indicate the cause or solution, but merely to >>> help analyze how critical your IC temperature is: Did you actually >>> measure the temperature of the IC? I recently bought an inexpensive >>> infrared thermometer (like:https://www.ebay.co.uk/itm/156810933790) >>> that can measure the temperature of small areas relatively accurately. >>> I made the experience that I cannot judge temperatures very well with my >> fingers. >>> According to Wikipedia, TTL ICs are specified for temperatures up to >>> 70 °C. This >>> temperature should obviously be avoided, but my fingers already >>> perceive anything above about 50 °C as "hot". >>> >>> I hope this can help a litte! >> Yes, I have an IR Thermometer and the chip gets to about 40 celsius. I > realise >> that this is well below the maximum rating, but I can smell the heat and > it >> worries me a bit. If I knew this was expected then I would be OK with it, > but it >> feels anomalous and I have felt the chip to be hotter than this sometimes. >> The observation about the negative voltages also concerns me a bit, > although >> I do have spares for the 74S299 should I need them. >> >> It looks now like the DC011 is just producing a DOT CLK output with > negative >> spikes. Maybe this is why later revisions introduced an inductor or maybe > it is >> just a bad DC011 or something is wrong with what is around the DC011. >> >> I am going to look at the DC011 inputs to see if anything looks amiss. The >> other thing I would like to do is to see what happens if I can add an > inductor >> to the output of the DC011. But I don't know how to read the spec on the >> printset to know what I might need. The printset says "BEAD, FERRITE >> .1380DX.380LG", can anyone tell me what this might mean in terms of an >> inductor that I could try? >> >> Thanks >> >> Rob >> >> >>> Ulli >>> >>> Am Sa., 29. Nov. 2025 um 09:44 Uhr schrieb Henk Gooijen via cctalk < >>> cctalk(a)classiccmp.org>: >>> >>>> Rob, >>>> >>>> I have a few silly thoughts, but maybe they can be useful. >>>> The negative going signal is something I would not be happy with, as >>>> it may damage the IC (over time). >>>> TTL does not like negative voltages on their pins. >>>> Is there between the DC011 (signal generating) and the LS299 (signal >>>> "user") wiring, or are they on the same PCB? >>>> In case of wiring, capacitive coupling may cause negative going >> voltages. >>>> Could a clamping diode with an as low as possible Vf (< 0.3 V) help >>>> to reduce the negative voltage? It is not a permanent solution, >>>> because the >>>> DC011 might be a bit unhappy with that diode, but for a test it >>>> might help to draw a conclusion. >>>> >>>> If all does not help, in getting the LS299 running cooler, consider >>>> some temperature conductive paste and a small "IC heatsink". Tie the >>>> heatsink onto the IC with a piece of waxed lacing. The IC can >>>> radiate more efficiently the generated heat, so that it can run >>>> cooler. This could drop temperature with some 10 degrees. >>>> >>>> Success hunting down this issue, >>>> Henk >>>> >>>> -----Oorspronkelijk bericht----- >>>> Van: Rob Jarratt via cctalk<cctalk(a)classiccmp.org> >>>> Verzonden: zaterdag 29 november 2025 08:11 >>>> Aan: 'Doug Jackson'<doug(a)doughq.com>;rob(a)jarratt.me.uk >>>> CC: 'General Discussion: On-Topic and Off-Topic Posts' < >>>> cctalk(a)classiccmp.org>; Rob Jarratt <robert.jarratt(a)ntlworld.com> >>>> Onderwerp: [cctalk] Re: Hot Video Shift Register on VT100 >>>> >>>> Yes, it is a negative voltage. I measured this by attaching the >>>> ground lead to the ground connection on the 74S299. >>>> >>>> >>>> >>>> The DC011 that is producing the CLK signal is socketed, but the one >>>> on my >>>> VT102 isnt. I would try swapping them to see what happens, but I >>>> dont really want to touch a fully working board. >>>> >>>> >>>> >>>> Thanks >>>> >>>> >>>> >>>> Rob >>>> >>>> >>>> >>>> From: Doug Jackson<doug(a)doughq.com> >>>> Sent: 28 November 2025 22:59 >>>> To:rob@jarratt.me.uk >>>> Cc: General Discussion: On-Topic and Off-Topic Posts < >>>> cctalk(a)classiccmp.org> >>>> Subject: Re: [cctalk] Re: Hot Video Shift Register on VT100 >>>> >>>> >>>> >>>> Is that a negative excursion at the bottom of the waveform? now low >>>> - looks like -0.3v to me - With '"logic, that will likely turn on >>>> the protection diodes on the inputs, making them warm. >>>> >>>> >>>> >>>> Double check where the ground actually is on the CRO display. >>>> >>>> >>>> >>>> It's also interesting that the input doesn't even reach 4v, let >>>> alone >> 5v. >>>> Whats driving that? >>>> >>>> >>>> >>>> >>>> >>>> Kindest regards, >>>> >>>> >>>> >>>> Doug Jackson >>>> >>>> >>>> >>>> em:doug@doughq.com <mailto:doug@doughq.com> >>>> >>>> ph: 0414 986878 >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> On Sat, 29 Nov 2025 at 08:52, Rob Jarratt >>>> <robert.jarratt(a)ntlworld.com <mailto:robert.jarratt@ntlworld.com> > >> wrote: >>>> I checked the CLK input for the 74S299 with the 74S299 removed and >>>> the signal is still spiky and looks like this: >>>> https://rjarratt.wordpress.com/wp-content/uploads/2025/11/vt102-74s2 >>>> 99 >>>> -clk-signal.png >>>> >>>> >>>> >>>> I removed the other load on this signal, the DC012, and the CLK >>>> signal still looked spiky. I also put back the 74S299 (now socketed) >>>> with >>>> DC012 removed and it still gets hot. I tried another new 74S299 just >>>> in case I had a bad one and that also got hot without a load on the >> output. >>>> >>>> >>>> I am thinking that it is either the spiky input or it is just >>>> expected to get this hot. >>>> >>>> >>>> >>>> Regards >>>> >>>> >>>> >>>> Rob >>>> >>>> >>>> >>>> From: Doug Jackson <doug(a)doughq.com <mailto:doug@doughq.com> > >>>> Sent: 25 November 2025 01:15 >>>> To:rob@jarratt.me.uk <mailto:rob@jarratt.me.uk> >>>> Cc: General Discussion: On-Topic and Off-Topic Posts < >>>> cctalk(a)classiccmp.org <mailto:cctalk@classiccmp.org> > >>>> Subject: Re: [cctalk] Re: Hot Video Shift Register on VT100 >>>> >>>> >>>> >>>> The oscilloscope will show you the actual driving waveform. >>>> >>>> >>>> >>>> You can then see the level of the spikes >>>> >>>> >>>> >>>> Kindest regards, >>>> >>>> >>>> >>>> Doug Jackson >>>> >>>> >>>> >>>> em:doug@doughq.com <mailto:doug@doughq.com> >>>> >>>> ph: 0414 986878 >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> On Tue, 25 Nov 2025 at 10:48, Rob Jarratt >>>> <robert.jarratt(a)ntlworld.com <mailto:robert.jarratt@ntlworld.com> > >> wrote: >>>> >>>> >>>>> -----Original Message----- >>>>> From: Doug Jackson via cctalk <cctalk(a)classiccmp.org <mailto: >>>> cctalk(a)classiccmp.org> > >>>>> Sent: 24 November 2025 23:04 >>>>> To: General Discussion: On-Topic and Off-Topic Posts < >>>> cctalk(a)classiccmp.org <mailto:cctalk@classiccmp.org> > >>>>> Cc: Doug Jackson <doug(a)doughq.com <mailto:doug@doughq.com> > >>>>> Subject: [cctalk] Re: Hot Video Shift Register on VT100 >>>>> >>>>> Another test would be to disconnect the output and see if that >>>>> runs the device cooler. Maybe the load, while not a short, is >>>>> simply too great >>>> for the >>>>> device. >>>> I think I can try this, the DC012 it drives is socketed. >>>> >>>>> But I am leaning towards the inputs containing spikes that need to >>>>> be dissipated as heat in clamping diodes. A decent CRO on the >>>>> device input >>>> pins >>>>> while it is out of circuit will show that as well. >>>> I guess CRO means Cathode Ray Oscilloscope? Not sure what you are >>>> suggesting I try here? >>>> >>>> >>>>> Kindest regards, >>>>> >>>>> Doug Jackson >>>>> >>>>> em:doug@doughq.com <mailto:doug@doughq.com> >>>>> ph: 0414 986878 >>>>> >>>>> >>>>> >>>>> >>>>> On Tue, 25 Nov 2025 at 09:52, Peter Coghlan via cctalk < >>>>> cctalk(a)classiccmp.org <mailto:cctalk@classiccmp.org> > wrote: >>>>> >>>>>>> Sorry if I wasn't clear in my earlier reply, but there were >>>>>>> some answers inline. The summary is that Vcc looks fine, there >>>>>>> does not seem to be any short on the outputs of the shift >>>>>>> register and the chip seems to be >>>>>> working >>>>>>> correctly. It just gets hot and I wonder if this could be due >>>>>>> to the CLK input being a bit spikier on the VT100 than on my > VT102? >>>>>>> Could this be >>>>>> why >>>>>>> later revisions of the VT100 introduced an inductor on the DOT >>>>>>> CLK output from the DC011? >>>>>>> >>>>>> Perhaps one way to test the hypothesis would be to insert an >>>>>> inductor like those used on the later revisions in the DOT CLK >>>>>> output and check whether >>>>>> a) everything still works and b) the shift register runs cooler? >>>>>> >>>>>> Regards, >>>>>> Peter Coghlan. >>>>>> >>>> > > ------------------------------ > > Message: 13 > Date: Sun, 30 Nov 2025 15:24:11 +0000 > From: Charles Morris<charlesmorris800(a)protonmail.com> > Subject: [cctalk] Re: Hot Video Shift Register on VT100 > To:cctalk@classiccmp.org > Message-ID:<bf019ff7-a240-4ec5-b6a3-749e6cd9b3af(a)protonmail.com> > Content-Type: text/plain; charset=utf-8 > > Keep in mind that ringing (artifact caused by the inductance of the > scope probe ground lead) can result in a false display of overshoots... > How short is your ground lead? > -Charles > > On 11/30/25 08:30, Rob Jarratt via cctalk wrote: >> I have traced the clock signal back. The MAS CLK input on the DC011 also has >> the negative spikes. This is coming from a 74S157. The input to that is an >> oscillator and that too has the negative spikes. >> >> So, it seems the 74S157 is just passing through the inputs. >> >> There is a capacitor across pins 4 and 2 of the oscillator (Vcc and Gnd), >> would a failure there cause this kind of negative spike? It seems unlikely >> to me, but would be happy to be corrected. >> >> The oscillator is rated at 24.0734MHz. I can find lots rated at exactly >> 24MHz and I guess the difference in frequency is small enough not to matter, >> right? >> >> I will order the part and also a new capacitor for it in case that is where >> the fault lies and see. >> >> Thanks >> >> Rob >> >> >>> -----Original Message----- >>> From: Rob Jarratt via cctalk<cctalk(a)classiccmp.org> >>> Sent: 30 November 2025 12:57 >>> To: 'General Discussion: On-Topic and Off-Topic Posts' >>> <cctalk(a)classiccmp.org> >>> Cc: 'Hans-Ulrich Hölscher'<vaxorcist(a)googlemail.com>; Rob Jarratt >>> <robert.jarratt(a)ntlworld.com> >>> Subject: [cctalk] Re: Hot Video Shift Register on VT100 >>> >>>> -----Original Message----- >>>> From: Hans-Ulrich Hölscher via cctalk<cctalk(a)classiccmp.org> >>>> Sent: 29 November 2025 09:17 >>>> To: General Discussion: On-Topic and Off-Topic Posts >>> <cctalk(a)classiccmp.org> >>>> Cc: Hans-Ulrich Hölscher<vaxorcist(a)googlemail.com> >>>> Subject: [cctalk] Re: Hot Video Shift Register on VT100 >>>> >>>> Hi Rob, >>>> this is not intended to indicate the cause or solution, but merely to >>>> help analyze how critical your IC temperature is: Did you actually >>>> measure the temperature of the IC? I recently bought an inexpensive >>>> infrared thermometer (like:https://www.ebay.co.uk/itm/156810933790) >>>> that can measure the temperature of small areas relatively accurately. >>>> I made the experience that I cannot judge temperatures very well with my >>> fingers. >>>> According to Wikipedia, TTL ICs are specified for temperatures up to >>>> 70 °C. This >>>> temperature should obviously be avoided, but my fingers already >>>> perceive anything above about 50 °C as "hot". >>>> >>>> I hope this can help a litte! >>> Yes, I have an IR Thermometer and the chip gets to about 40 celsius. I >> realise >>> that this is well below the maximum rating, but I can smell the heat and >> it >>> worries me a bit. If I knew this was expected then I would be OK with it, >> but it >>> feels anomalous and I have felt the chip to be hotter than this sometimes. >>> The observation about the negative voltages also concerns me a bit, >> although >>> I do have spares for the 74S299 should I need them. >>> >>> It looks now like the DC011 is just producing a DOT CLK output with >> negative >>> spikes. Maybe this is why later revisions introduced an inductor or maybe >> it is >>> just a bad DC011 or something is wrong with what is around the DC011. >>> >>> I am going to look at the DC011 inputs to see if anything looks amiss. The >>> other thing I would like to do is to see what happens if I can add an >> inductor >>> to the output of the DC011. But I don't know how to read the spec on the >>> printset to know what I might need. The printset says "BEAD, FERRITE >>> .1380DX.380LG", can anyone tell me what this might mean in terms of an >>> inductor that I could try? >>> >>> Thanks >>> >>> Rob >>> >>> >>>> Ulli >>>> >>>> Am Sa., 29. Nov. 2025 um 09:44 Uhr schrieb Henk Gooijen via cctalk < >>>> cctalk(a)classiccmp.org>: >>>> >>>>> Rob, >>>>> >>>>> I have a few silly thoughts, but maybe they can be useful. >>>>> The negative going signal is something I would not be happy with, as >>>>> it may damage the IC (over time). >>>>> TTL does not like negative voltages on their pins. >>>>> Is there between the DC011 (signal generating) and the LS299 (signal >>>>> "user") wiring, or are they on the same PCB? >>>>> In case of wiring, capacitive coupling may cause negative going >>> voltages. >>>>> Could a clamping diode with an as low as possible Vf (< 0.3 V) help >>>>> to reduce the negative voltage? It is not a permanent solution, >>>>> because the >>>>> DC011 might be a bit unhappy with that diode, but for a test it >>>>> might help to draw a conclusion. >>>>> >>>>> If all does not help, in getting the LS299 running cooler, consider >>>>> some temperature conductive paste and a small "IC heatsink". Tie the >>>>> heatsink onto the IC with a piece of waxed lacing. The IC can >>>>> radiate more efficiently the generated heat, so that it can run >>>>> cooler. This could drop temperature with some 10 degrees. >>>>> >>>>> Success hunting down this issue, >>>>> Henk >>>>> >>>>> -----Oorspronkelijk bericht----- >>>>> Van: Rob Jarratt via cctalk<cctalk(a)classiccmp.org> >>>>> Verzonden: zaterdag 29 november 2025 08:11 >>>>> Aan: 'Doug Jackson'<doug(a)doughq.com>;rob(a)jarratt.me.uk >>>>> CC: 'General Discussion: On-Topic and Off-Topic Posts' < >>>>> cctalk(a)classiccmp.org>; Rob Jarratt <robert.jarratt(a)ntlworld.com> >>>>> Onderwerp: [cctalk] Re: Hot Video Shift Register on VT100 >>>>> >>>>> Yes, it is a negative voltage. I measured this by attaching the >>>>> ground lead to the ground connection on the 74S299. >>>>> >>>>> >>>>> >>>>> The DC011 that is producing the CLK signal is socketed, but the one >>>>> on my >>>>> VT102 isnt. I would try swapping them to see what happens, but I >>>>> dont really want to touch a fully working board. >>>>> >>>>> >>>>> >>>>> Thanks >>>>> >>>>> >>>>> >>>>> Rob >>>>> >>>>> >>>>> >>>>> From: Doug Jackson<doug(a)doughq.com> >>>>> Sent: 28 November 2025 22:59 >>>>> To:rob@jarratt.me.uk >>>>> Cc: General Discussion: On-Topic and Off-Topic Posts < >>>>> cctalk(a)classiccmp.org> >>>>> Subject: Re: [cctalk] Re: Hot Video Shift Register on VT100 >>>>> >>>>> >>>>> >>>>> Is that a negative excursion at the bottom of the waveform? now low >>>>> - looks like -0.3v to me - With '"logic, that will likely turn on >>>>> the protection diodes on the inputs, making them warm. >>>>> >>>>> >>>>> >>>>> Double check where the ground actually is on the CRO display. >>>>> >>>>> >>>>> >>>>> It's also interesting that the input doesn't even reach 4v, let >>>>> alone >>> 5v. >>>>> Whats driving that? >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> Kindest regards, >>>>> >>>>> >>>>> >>>>> Doug Jackson >>>>> >>>>> >>>>> >>>>> em:doug@doughq.com <mailto:doug@doughq.com> >>>>> >>>>> ph: 0414 986878 >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> On Sat, 29 Nov 2025 at 08:52, Rob Jarratt >>>>> <robert.jarratt(a)ntlworld.com <mailto:robert.jarratt@ntlworld.com> > >>> wrote: >>>>> I checked the CLK input for the 74S299 with the 74S299 removed and >>>>> the signal is still spiky and looks like this: >>>>> https://rjarratt.wordpress.com/wp-content/uploads/2025/11/vt102-74s2 >>>>> 99 >>>>> -clk-signal.png >>>>> >>>>> >>>>> >>>>> I removed the other load on this signal, the DC012, and the CLK >>>>> signal still looked spiky. I also put back the 74S299 (now socketed) >>>>> with >>>>> DC012 removed and it still gets hot. I tried another new 74S299 just >>>>> in case I had a bad one and that also got hot without a load on the >>> output. >>>>> >>>>> I am thinking that it is either the spiky input or it is just >>>>> expected to get this hot. >>>>> >>>>> >>>>> >>>>> Regards >>>>> >>>>> >>>>> >>>>> Rob >>>>> >>>>> >>>>> >>>>> From: Doug Jackson <doug(a)doughq.com <mailto:doug@doughq.com> > >>>>> Sent: 25 November 2025 01:15 >>>>> To:rob@jarratt.me.uk <mailto:rob@jarratt.me.uk> >>>>> Cc: General Discussion: On-Topic and Off-Topic Posts < >>>>> cctalk(a)classiccmp.org <mailto:cctalk@classiccmp.org> > >>>>> Subject: Re: [cctalk] Re: Hot Video Shift Register on VT100 >>>>> >>>>> >>>>> >>>>> The oscilloscope will show you the actual driving waveform. >>>>> >>>>> >>>>> >>>>> You can then see the level of the spikes >>>>> >>>>> >>>>> >>>>> Kindest regards, >>>>> >>>>> >>>>> >>>>> Doug Jackson >>>>> >>>>> >>>>> >>>>> em:doug@doughq.com <mailto:doug@doughq.com> >>>>> >>>>> ph: 0414 986878 >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> On Tue, 25 Nov 2025 at 10:48, Rob Jarratt >>>>> <robert.jarratt(a)ntlworld.com <mailto:robert.jarratt@ntlworld.com> > >>> wrote: >>>>> >>>>>> -----Original Message----- >>>>>> From: Doug Jackson via cctalk <cctalk(a)classiccmp.org <mailto: >>>>> cctalk(a)classiccmp.org> > >>>>>> Sent: 24 November 2025 23:04 >>>>>> To: General Discussion: On-Topic and Off-Topic Posts < >>>>> cctalk(a)classiccmp.org <mailto:cctalk@classiccmp.org> > >>>>>> Cc: Doug Jackson <doug(a)doughq.com <mailto:doug@doughq.com> > >>>>>> Subject: [cctalk] Re: Hot Video Shift Register on VT100 >>>>>> >>>>>> Another test would be to disconnect the output and see if that >>>>>> runs the device cooler. Maybe the load, while not a short, is >>>>>> simply too great >>>>> for the >>>>>> device. >>>>> I think I can try this, the DC012 it drives is socketed. >>>>> >>>>>> But I am leaning towards the inputs containing spikes that need to >>>>>> be dissipated as heat in clamping diodes. A decent CRO on the >>>>>> device input >>>>> pins >>>>>> while it is out of circuit will show that as well. >>>>> I guess CRO means Cathode Ray Oscilloscope? Not sure what you are >>>>> suggesting I try here? >>>>> >>>>> >>>>>> Kindest regards, >>>>>> >>>>>> Doug Jackson >>>>>> >>>>>> em:doug@doughq.com <mailto:doug@doughq.com> >>>>>> ph: 0414 986878 >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Tue, 25 Nov 2025 at 09:52, Peter Coghlan via cctalk < >>>>>> cctalk(a)classiccmp.org <mailto:cctalk@classiccmp.org> > wrote: >>>>>> >>>>>>>> Sorry if I wasn't clear in my earlier reply, but there were >>>>>>>> some answers inline. The summary is that Vcc looks fine, there >>>>>>>> does not seem to be any short on the outputs of the shift >>>>>>>> register and the chip seems to be >>>>>>> working >>>>>>>> correctly. It just gets hot and I wonder if this could be due >>>>>>>> to the CLK input being a bit spikier on the VT100 than on my >> VT102? >>>>>>>> Could this be >>>>>>> why >>>>>>>> later revisions of the VT100 introduced an inductor on the DOT >>>>>>>> CLK output from the DC011? >>>>>>>> >>>>>>> Perhaps one way to test the hypothesis would be to insert an >>>>>>> inductor like those used on the later revisions in the DOT CLK >>>>>>> output and check whether >>>>>>> a) everything still works and b) the shift register runs cooler? >>>>>>> >>>>>>> Regards, >>>>>>> Peter Coghlan. >>>>>>> > > > ------------------------------ > > Message: 14 > Date: Sun, 30 Nov 2025 16:23:44 -0000 > From: "Rob Jarratt"<robert.jarratt(a)ntlworld.com> > Subject: [cctalk] Re: Hot Video Shift Register on VT100 > To: "'General Discussion: On-Topic and Off-Topic Posts'" > <cctalk(a)classiccmp.org> > Cc: 'Charles Morris'<charlesmorris800(a)protonmail.com> > Message-ID:<014a01dc6215$b2b40610$181c1230$(a)ntlworld.com> > Content-Type: text/plain; charset="UTF-8" > > > >> -----Original Message----- >> From: Charles Morris via cctalk<cctalk(a)classiccmp.org> >> Sent: 30 November 2025 15:24 >> To:cctalk@classiccmp.org >> Cc: Charles Morris<charlesmorris800(a)protonmail.com> >> Subject: [cctalk] Re: Hot Video Shift Register on VT100 >> >> Keep in mind that ringing (artifact caused by the inductance of the scope >> probe ground lead) can result in a false display of overshoots... >> How short is your ground lead? > Quite short. But what I saw is the exact same shape as the input to the chip that gets hot and measuring the same chip on a VT102 I don't see this. So I am fairly sure this is real. > > >> -Charles >> >> On 11/30/25 08:30, Rob Jarratt via cctalk wrote: >>> I have traced the clock signal back. The MAS CLK input on the DC011 >>> also has the negative spikes. This is coming from a 74S157. The input >>> to that is an oscillator and that too has the negative spikes. >>> >>> So, it seems the 74S157 is just passing through the inputs. >>> >>> There is a capacitor across pins 4 and 2 of the oscillator (Vcc and >>> Gnd), would a failure there cause this kind of negative spike? It >>> seems unlikely to me, but would be happy to be corrected. >>> >>> The oscillator is rated at 24.0734MHz. I can find lots rated at >>> exactly 24MHz and I guess the difference in frequency is small enough >>> not to matter, right? >>> >>> I will order the part and also a new capacitor for it in case that is >>> where the fault lies and see. >>> >>> Thanks >>> >>> Rob >>> >>> >>>> -----Original Message----- >>>> From: Rob Jarratt via cctalk<cctalk(a)classiccmp.org> >>>> Sent: 30 November 2025 12:57 >>>> To: 'General Discussion: On-Topic and Off-Topic Posts' >>>> <cctalk(a)classiccmp.org> >>>> Cc: 'Hans-Ulrich Hölscher'<vaxorcist(a)googlemail.com>; Rob Jarratt >>>> <robert.jarratt(a)ntlworld.com> >>>> Subject: [cctalk] Re: Hot Video Shift Register on VT100 >>>> >>>>> -----Original Message----- >>>>> From: Hans-Ulrich Hölscher via cctalk<cctalk(a)classiccmp.org> >>>>> Sent: 29 November 2025 09:17 >>>>> To: General Discussion: On-Topic and Off-Topic Posts >>>> <cctalk(a)classiccmp.org> >>>>> Cc: Hans-Ulrich Hölscher<vaxorcist(a)googlemail.com> >>>>> Subject: [cctalk] Re: Hot Video Shift Register on VT100 >>>>> >>>>> Hi Rob, >>>>> this is not intended to indicate the cause or solution, but merely >>>>> to help analyze how critical your IC temperature is: Did you >>>>> actually measure the temperature of the IC? I recently bought an >>>>> inexpensive infrared thermometer >>>>> (like:https://www.ebay.co.uk/itm/156810933790) >>>>> that can measure the temperature of small areas relatively accurately. >>>>> I made the experience that I cannot judge temperatures very well >>>>> with my >>>> fingers. >>>>> According to Wikipedia, TTL ICs are specified for temperatures up to >>>>> 70 °C. This >>>>> temperature should obviously be avoided, but my fingers already >>>>> perceive anything above about 50 °C as "hot". >>>>> >>>>> I hope this can help a litte! >>>> Yes, I have an IR Thermometer and the chip gets to about 40 celsius. >>>> I >>> realise >>>> that this is well below the maximum rating, but I can smell the heat >>>> and >>> it >>>> worries me a bit. If I knew this was expected then I would be OK with >>>> it, >>> but it >>>> feels anomalous and I have felt the chip to be hotter than this sometimes. >>>> The observation about the negative voltages also concerns me a bit, >>> although >>>> I do have spares for the 74S299 should I need them. >>>> >>>> It looks now like the DC011 is just producing a DOT CLK output with >>> negative >>>> spikes. Maybe this is why later revisions introduced an inductor or >>>> maybe >>> it is >>>> just a bad DC011 or something is wrong with what is around the DC011. >>>> >>>> I am going to look at the DC011 inputs to see if anything looks >>>> amiss. The other thing I would like to do is to see what happens if I >>>> can add an >>> inductor >>>> to the output of the DC011. But I don't know how to read the spec on >>>> the printset to know what I might need. The printset says "BEAD, >>>> FERRITE .1380DX.380LG", can anyone tell me what this might mean in >>>> terms of an inductor that I could try? >>>> >>>> Thanks >>>> >>>> Rob >>>> >>>> >>>>> Ulli >>>>> >>>>> Am Sa., 29. Nov. 2025 um 09:44 Uhr schrieb Henk Gooijen via cctalk < >>>>> cctalk(a)classiccmp.org>: >>>>> >>>>>> Rob, >>>>>> >>>>>> I have a few silly thoughts, but maybe they can be useful. >>>>>> The negative going signal is something I would not be happy with, >>>>>> as it may damage the IC (over time). >>>>>> TTL does not like negative voltages on their pins. >>>>>> Is there between the DC011 (signal generating) and the LS299 >>>>>> (signal >>>>>> "user") wiring, or are they on the same PCB? >>>>>> In case of wiring, capacitive coupling may cause negative going >>>> voltages. >>>>>> Could a clamping diode with an as low as possible Vf (< 0.3 V) help >>>>>> to reduce the negative voltage? It is not a permanent solution, >>>>>> because the >>>>>> DC011 might be a bit unhappy with that diode, but for a test it >>>>>> might help to draw a conclusion. >>>>>> >>>>>> If all does not help, in getting the LS299 running cooler, consider >>>>>> some temperature conductive paste and a small "IC heatsink". Tie >>>>>> the heatsink onto the IC with a piece of waxed lacing. The IC can >>>>>> radiate more efficiently the generated heat, so that it can run >>>>>> cooler. This could drop temperature with some 10 degrees. >>>>>> >>>>>> Success hunting down this issue, >>>>>> Henk >>>>>> >>>>>> -----Oorspronkelijk bericht----- >>>>>> Van: Rob Jarratt via cctalk<cctalk(a)classiccmp.org> >>>>>> Verzonden: zaterdag 29 november 2025 08:11 >>>>>> Aan: 'Doug Jackson'<doug(a)doughq.com>;rob(a)jarratt.me.uk >>>>>> CC: 'General Discussion: On-Topic and Off-Topic Posts' < >>>>>> cctalk(a)classiccmp.org>; Rob Jarratt <robert.jarratt(a)ntlworld.com> >>>>>> Onderwerp: [cctalk] Re: Hot Video Shift Register on VT100 >>>>>> >>>>>> Yes, it is a negative voltage. I measured this by attaching the >>>>>> ground lead to the ground connection on the 74S299. >>>>>> >>>>>> >>>>>> >>>>>> The DC011 that is producing the CLK signal is socketed, but the one >>>>>> on my >>>>>> VT102 isn’t. I would try swapping them to see what happens, but I >>>>>> don’t really want to touch a fully working board. >>>>>> >>>>>> >>>>>> >>>>>> Thanks >>>>>> >>>>>> >>>>>> >>>>>> Rob >>>>>> >>>>>> >>>>>> >>>>>> From: Doug Jackson<doug(a)doughq.com> >>>>>> Sent: 28 November 2025 22:59 >>>>>> To:rob@jarratt.me.uk >>>>>> Cc: General Discussion: On-Topic and Off-Topic Posts < >>>>>> cctalk(a)classiccmp.org> >>>>>> Subject: Re: [cctalk] Re: Hot Video Shift Register on VT100 >>>>>> >>>>>> >>>>>> >>>>>> Is that a negative excursion at the bottom of the waveform? now >>>>>> low >>>>>> - looks like -0.3v to me - With '"logic, that will likely turn on >>>>>> the protection diodes on the inputs, making them warm. >>>>>> >>>>>> >>>>>> >>>>>> Double check where the ground actually is on the CRO display. >>>>>> >>>>>> >>>>>> >>>>>> It's also interesting that the input doesn't even reach 4v, let >>>>>> alone >>>> 5v. >>>>>> Whats driving that? >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> Kindest regards, >>>>>> >>>>>> >>>>>> >>>>>> Doug Jackson >>>>>> >>>>>> >>>>>> >>>>>> em:doug@doughq.com <mailto:doug@doughq.com> >>>>>> >>>>>> ph: 0414 986878 >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Sat, 29 Nov 2025 at 08:52, Rob Jarratt >>>>>> <robert.jarratt(a)ntlworld.com <mailto:robert.jarratt@ntlworld.com> > >>>> wrote: >>>>>> I checked the CLK input for the 74S299 with the 74S299 removed and >>>>>> the signal is still spiky and looks like this: >>>>>> https://rjarratt.wordpress.com/wp-content/uploads/2025/11/vt102-74s >>>>>> 2 >>>>>> 99 >>>>>> -clk-signal.png >>>>>> >>>>>> >>>>>> >>>>>> I removed the other load on this signal, the DC012, and the CLK >>>>>> signal still looked spiky. I also put back the 74S299 (now >>>>>> socketed) with >>>>>> DC012 removed and it still gets hot. I tried another new 74S299 >>>>>> just in case I had a bad one and that also got hot without a load >>>>>> on the >>>> output. >>>>>> >>>>>> I am thinking that it is either the spiky input or it is just >>>>>> expected to get this hot. >>>>>> >>>>>> >>>>>> >>>>>> Regards >>>>>> >>>>>> >>>>>> >>>>>> Rob >>>>>> >>>>>> >>>>>> >>>>>> From: Doug Jackson <doug(a)doughq.com <mailto:doug@doughq.com> >>>>>> Sent: 25 November 2025 01:15 >>>>>> To:rob@jarratt.me.uk <mailto:rob@jarratt.me.uk> >>>>>> Cc: General Discussion: On-Topic and Off-Topic Posts < >>>>>> cctalk(a)classiccmp.org <mailto:cctalk@classiccmp.org> > >>>>>> Subject: Re: [cctalk] Re: Hot Video Shift Register on VT100 >>>>>> >>>>>> >>>>>> >>>>>> The oscilloscope will show you the actual driving waveform. >>>>>> >>>>>> >>>>>> >>>>>> You can then see the level of the spikes >>>>>> >>>>>> >>>>>> >>>>>> Kindest regards, >>>>>> >>>>>> >>>>>> >>>>>> Doug Jackson >>>>>> >>>>>> >>>>>> >>>>>> em:doug@doughq.com <mailto:doug@doughq.com> >>>>>> >>>>>> ph: 0414 986878 >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Tue, 25 Nov 2025 at 10:48, Rob Jarratt >>>>>> <robert.jarratt(a)ntlworld.com <mailto:robert.jarratt@ntlworld.com> > >>>> wrote: >>>>>> >>>>>>> -----Original Message----- >>>>>>> From: Doug Jackson via cctalk <cctalk(a)classiccmp.org <mailto: >>>>>> cctalk(a)classiccmp.org> > >>>>>>> Sent: 24 November 2025 23:04 >>>>>>> To: General Discussion: On-Topic and Off-Topic Posts < >>>>>> cctalk(a)classiccmp.org <mailto:cctalk@classiccmp.org> > >>>>>>> Cc: Doug Jackson <doug(a)doughq.com <mailto:doug@doughq.com> > >>>>>>> Subject: [cctalk] Re: Hot Video Shift Register on VT100 >>>>>>> >>>>>>> Another test would be to disconnect the output and see if that >>>>>>> runs the device cooler. Maybe the load, while not a short, is >>>>>>> simply too great >>>>>> for the >>>>>>> device. >>>>>> I think I can try this, the DC012 it drives is socketed. >>>>>> >>>>>>> But I am leaning towards the inputs containing spikes that need to >>>>>>> be dissipated as heat in clamping diodes. A decent CRO on the >>>>>>> device input >>>>>> pins >>>>>>> while it is out of circuit will show that as well. >>>>>> I guess CRO means Cathode Ray Oscilloscope? Not sure what you are >>>>>> suggesting I try here? >>>>>> >>>>>> >>>>>>> Kindest regards, >>>>>>> >>>>>>> Doug Jackson >>>>>>> >>>>>>> em:doug@doughq.com <mailto:doug@doughq.com> >>>>>>> ph: 0414 986878 >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Tue, 25 Nov 2025 at 09:52, Peter Coghlan via cctalk < >>>>>>> cctalk(a)classiccmp.org <mailto:cctalk@classiccmp.org> > wrote: >>>>>>> >>>>>>>>> Sorry if I wasn't clear in my earlier reply, but there were some >>>>>>>>> answers inline. The summary is that Vcc looks fine, there does >>>>>>>>> not seem to be any short on the outputs of the shift register >>>>>>>>> and the chip seems to be >>>>>>>> working >>>>>>>>> correctly. It just gets hot and I wonder if this could be due to >>>>>>>>> the CLK input being a bit spikier on the VT100 than on my >>> VT102? >>>>>>>>> Could this be >>>>>>>> why >>>>>>>>> later revisions of the VT100 introduced an inductor on the DOT >>>>>>>>> CLK output from the DC011? >>>>>>>>> >>>>>>>> Perhaps one way to test the hypothesis would be to insert an >>>>>>>> inductor like those used on the later revisions in the DOT CLK >>>>>>>> output and check whether >>>>>>>> a) everything still works and b) the shift register runs cooler? >>>>>>>> >>>>>>>> Regards, >>>>>>>> Peter Coghlan. >>>>>>>> >>>>>>

5 months, 2 weeks

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Subject: Friden Flexowriter models

by Tuccio

I had one of these back in 1978ish. I remember that the coding was ASCII, but “inverted” i.e. mark and space were reversed. Not sure if yours is the same. Good luck. Sent from my iPad > On Nov 30, 2025, at 1:00 PM, cctalk-request(a)classiccmp.org wrote: > > Subject: [cctalk] Friden Flexowriter models

5 months, 3 weeks

2
1
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VAX and OpenVMS

by Peter Ekstrom

Ok, started playing with the SIMH vax8600 simulator and OpenVMS 7.3 Hobbyist. I know they discontinued the hobbyist license program years ago, but does one actually need a license to run it? Or would an older version like 5.x or something be better? The OpenVMS community license is only for Alpha, Itanium and some x86_64 architectures so I'm sure that wouldn't work in a simulated VAX? - Peter

5 months, 3 weeks

20
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Hot Video Shift Register on VT100

by Rob Jarratt

(sending again from a different email address as I don't think my first email got through, apologies if this is a duplicate) I have a VT100 that I was working on a while back and then set aside for a bit. I have started to look at it again. I have noticed that the Video Shift Register, a 74S299, gets very hot, I can smell the heat and the chip gets almost too hot to touch, reaching almost 40 celsius. I have a working VT102 for comparison and the same chip there does not get so hot (it reaches about 30 celsius). I have already tried replacing the chip, but the new one gets equally hot. I looked at the signals the chip is receiving and the one that stands out as different is the CLK input (pin 12). It looks like this: https://rjarratt.wordpress.com/wp-content/uploads/2024/04/vt100-74s299-clk-s ignal.png. On the VT102 it looks like this: https://rjarratt.wordpress.com/wp-content/uploads/2025/11/vt102-74s299-clk-s ignal.png. It is much spikier on the VT100 and I was told at one point that this could be the cause of the hot running for the chip. Is that a reasonable assumption? Assuming the spikes are the cause of the hot running. I am trying to see why there is a difference. I have noticed that on the VT102 there is a 68R resistor between the DC011 which produces the signal and the 74S299. You can see this as R86 in the VT101 printset https://bitsavers.org/pdf/dec/terminal/vt101/MP-01066-00C_VT101_Family_Field _Maintenance_Print_Set_Apr82.pdf (p47 of the PDF). The VT100 printset dated Feb 82 https://bitsavers.org/pdf/dec/terminal/vt100/MP00633_VT100_Schematic_Feb82.p df shows an inductor L8 being used (PDF p17), but my VT100 does not have this and so must be described by the March 80 printset https://bitsavers.org/pdf/dec/terminal/vt100/MP00633_VT100_Mar80.pdf (PDF p17). Could the absence of L8 explain the spikier DOT CLK signal and the hotter 74S299? Incidentally, I suspect that the flyback transformer on my VT100 has failed. If anyone has a flyback transformer going spare, especially in the UK, then I would love to hear from you. Thanks Rob

5 months, 3 weeks

12
22
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Conductive material in rubber dome

by me＠scifidan.com

I just acquired a TRS-80 model 102, my first of that model. Everything is great other than three keys. The 2 keys works intermittently, q, and [ don't work. Having checked the schematic, the keys have no commonality on the circuit. Before I pull the cap off the switch, I know that the rubber dome inside has material on the inner part that meets with the silver contacts to complete the circuit. I'm told this material will wear out or lose conductivity. I reflowed the solder joints on the pcb and this didn't help. Other people have simply replaced the rubber dome from another dead 102's keyboard. But, I'd rather attempt applying new material inside that dome. I'm hoping there is an inexpensive and mainstream solution I can buy at home depot or something. Any tips? Daniel sysop | Air & Wave BBS finger | calcmandan(a)bbs.erb.pw

5 months, 3 weeks

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leave

by Ralph M. Hockens

leave

5 months, 3 weeks

4
3
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Re: leave

by junk myalternateemail.com

Shoes? Heck, I have to put pants on first.

5 months, 3 weeks

1
0
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BDV11 programming information

by Peter Ekstrom

Does anyone know if there is any programming information about the BDV11 card? I have disassembled the ROM files for it and I see they do various operations with the registers on the card, but it is not clear to me exactly what they are doing. - Peter

5 months, 3 weeks

3
5
0 0

OT Scotch Type 871 Tape Reel?

by Holm Tiffe

Hi all, I'm trying to sell an old Scotch tape reel on Ebay Kleinanzeigen here in germany. It's box is labeled 871-1-3600 R41 which I think means Type 871, 1 Inch and 3600 ft, Don't hve an idea about R41. Stock No: 84-9800-5294-2 I've bought that myself in a error..needed an Data tape to this time. Now one asks if that is an vintage video tape for the philisp EL3400 Recorder.. Has someone an idea what kind of tape that may be? Thx, Holm -- Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, Goethestrasse 15, 09569 Oederan, USt-Id: DE253710583 info(a)tsht.de Tel +49 37292 709778 Mobil: 0172 8790 741

5 months, 3 weeks

1
0
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Someone is letting go of a Data General Eclipse S/20 in Missouri

by Christian Liendo

This is not my ad, but I saw this and I figured someone would be interested and reach out. https://www.reddit.com/r/VintageComputers/comments/1oxu9h5/data_general_ecl…

5 months, 3 weeks

1
0
0 0

WINdows-1985

by Murray McCullough

According to history Windows 1 was introduced to the world on Nov. 20, 1985, 40 years ago, minus 2 days. Prior to this Windows was first announced in 1983(vaporware) but…An even earlier development was Interface Manager. What we have now is much more and ‘better’ but for classic computing I still prefer WIN 3.1. Happy computing. Murray 🙂

6 months

13
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Depraz Mouse, Type D 83 / P, Excellent Condition, Looking to Establish Value and Sell

by microprint314＠gmail.com

I found a Depraz mouse the other day (Type D 83 / P) while going through moving boxes. I used to - long time ago - make things out of broken or disassembled computer gear. There was the most amazing store in Dover, NJ called Second Byte where I spent too much time and money (according to my ex-wife). I purchased this mouse 30 years ago with no particular project in mind, and it has just stayed packed away. I'm looking to sell it but I admittedly don't know what it's worth. I see two of them on eBay for $20-$30K, but don't see any Sold Items as a reference. Those sale prices sound largely aspirational. The mouse is in pretty amazing physical condition, with only basic scuffing on the red surface. The larger spots you see are reflections. The cable has scuffs but no fraying at all. The ball turns when the mouse is rolled. No pins are bent on the connector (RS-232 / DB9?). The three buttons click. Any insight - or offers - is welcomed. Thanks.

6 months

13
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Re: Seagate half high hard drive face plate & cables

by Peter Ekstrom

Mike, Where are you located? I am in the US in Georgia. I have several of each of those connectors. - Peter On Fri, Nov 21, 2025 at 3:42 PM Mike Katz <bitwiz(a)12bitsbest.com> wrote: > 20 and 34 pin edge (2 each) and 20 and 34 pin female dual in line (1 > each). I have the ribbon cable and the tool > > Thank you > > On Nov 21, 2025 12:19 PM, Peter Ekstrom <epekstrom(a)gmail.com> wrote: > > Mike, > > Which connectors is it you need? > > -Peter > > On Fri, Nov 21, 2025 at 1:08 PM Mike Katz via cctalk < > cctalk(a)classiccmp.org> wrote: > > > Paul, > > The connectors are about $5 apiece and I would need 7 connectors. I > have the cable and tool. > > My goal for asking was to see if anyone had a spare cable or two and > save them from eventually going in the land fill. > > Thank you for your help, > > Mike > > On 11/21/2025 11:17 AM, Paul Koning via cctalk wrote: > > For that matter, since the connectors are insulation displacement type, > you can assemble your own: buy the connectors and a length of table, cut > pieces to size, and assemble the connectors onto the cable. A press is > normally used for that, but a vise should do the job too. > > > > paul > > > >> On Nov 21, 2025, at 11:03 AM, Paul Koning via cctalk < > cctalk(a)classiccmp.org> wrote: > >> > >> General comment on cables like that: in the past I have obtained flat > ribbon cable assemblies from Digikey. If you're dealing with a cable > that's simply a ribbon of width N and a connector at each end, companies > like that can supply them easily and cheaply, in any length you want. > >> > >> paul > >> > >>> On Nov 20, 2025, at 9:40 PM, Mike Katz via cctalk < > cctalk(a)classiccmp.org> wrote: > >>> > >>> Does anyone out there have a spare 1/2 high 5 1/4" Seagate MFM hard > drive face plate (ST-221, ST-251, etc.) that they can let go cheap? > >>> > >>> And also a 34 conductor dual drive cable and a single 20 on single > drive cable? > >>> > >>> Thank you. > >>> > >>> Contact me off list at bitwiz(a)12bitsbest.com > > >

6 months

1
0
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Seagate half high hard drive face plate & cables

by Mike Katz

Does anyone out there have a spare 1/2 high 5 1/4" Seagate MFM hard drive face plate (ST-221, ST-251, etc.) that they can let go cheap? And also a 34 conductor dual drive cable and a single 20 on single drive cable? Thank you. Contact me off list at bitwiz(a)12bitsbest.com

6 months

6
11
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Various vintage computers and peripherals for sale

by martin .

As we're emigrating soon, I am starting so find a new home for my collection of vintage computers and peripherals. On offer today is: Dec PDP 8E* ==========on a standA list of modules included in the link below. including with the machine comes: - Rail mounting hardware - Spare power supply - A long flat cable - Bootstrap card M847E - 32k SRAM + Bootstrap card from Vincent Slyngstad (new kit, unassembled) ASR33 Teletype* ==============on its original stand Hazeltine H2000 terminal* ========================in pristine condition on a stand Hazeltine H2000 terminal========================probably not working (got somehow damaged during transport from last seller to me, and I never got around checking out what's wrong) Tektronix 4014-1* Graphics Terminal ===================================on its original stand Please make an offer for either some or for all of the items (to martin(a)meiner.ch). *) Items marked with a star were functioning well a few years ago when I was actively acquiring them. As times went by, it could be that one or the other may need TLC. I have not tested them again for full functionality. Items are located near Zurich/Switzerland. It is the buyer's responsibility to either pick the items up or to arrange packing and shipping by a forwarder. Here a link to cloud storage showing photos and other information of the units: http://e.pc.cd/o3sy6alK More equipment to follow in a few weeks / months (will rather be elder calculators).

6 months

1
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Replacements for DEC 3639

by Christian Corti

It seems that nowadays you can't get *any* replacement for failing DEC 3639 aka 2N3639 transistors. All parts are obsolete and unobtanium, e.g. 2N3640, PN3640, MMBT3640 and so on. So, what can be used instead? The most important electrical parameter is the storage time. It needs to be *very* low, around 20-30 ns. Does it mean that a failing PDP-8 will stay a dead PDP-8 from now on? Christian

6 months

14
39
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ST-251 MFM Hard Drive sector size question

by Mike Katz

I have an ST-251 42MB MFM hard disk drive. The documentation says the drive is 512 bytes per sector. I don't know if this is fixed (hard sectored) or not. My problem is my operating system (OS/9 Level II) wants 256 bytes per sector. The OMTI 20C-1 controller can handle that but I'm not sure if the ST-251 can. Does anyone know if the ST-251 can support 256 bytes per sector and/or how to configure it for 256 bytes per sector? Thank you, Mike

6 months

8
8
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Ancient versions of the VAX Workstation Software (VWS)

by Hans-Ulrich Hölscher

I'm looking for ancient versions of the VAX Workstation Software (VWS) for my software collection and for my VAXstation I: - V1.0 - V1.1 - V2.0 - V3.0 V1.0 (which was called "uVMS VAXstation I graphics/windowing softwarere" back then) and V1.1 are the most wanted ones, because they are the only ones that run on MicroVMS V4.0 for the VAXstation I. Version 1.0 was shipped on two RX50s, labeled “VSI010 1/2” and “VSI010 2/2”; later versions grew bigger and from V2.0 onwards TK50s were used besides RX50 floppies as well. Best Regards, Ulli

6 months

1
0
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Apple ADB Mouse

by Cameron Kelly

Hello, I am wondering if anyone here would be willing to part with their Apple ADB Mouse and is located within Canada? Best Regards, Cameron

6 months

1
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80386 - 1985

by Murray McCullough

40 years ago this year Intel came out with the 80386 – 386 – or i386. Either seems to be correct. What this meant was a memory address of 4GB, far beyond what an average computer user would need or want, but was so much more than previously(8086, 80286); ‘true’ multi-tasking which for the average computer user didn’t mean all that much; and paging, which made virtualization possible- experimenters were over-joyed! What all this contributed to was the end of the classical/vintage-computing era. Whether this began the time of open-source OS development is debatable! Happy computing? Murray 🙂

6 months, 1 week

16
33
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Unix V4

by Paul Koning

https://discuss.systems/@ricci/115504720054699983 and https://www.theregister.com/2025/11/07/unix_fourth_edition_tape_rediscovere… Amazing. paul

6 months, 1 week

6
7
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what is it? 3850 stuff

by Donald Whittemore

Got this on eBay. 7 3850 cartridges, a piece of mag tape and some metal device in a nice box. I am trying to determine what the metal thing is. Some kind of alignment tool? For cartridge insertion in MSS unit, not track alignment? https://www.myimagecollection.com/whatisit/pic1.jpg https://www.myimagecollection.com/whatisit/pic2.jpg

6 months, 1 week

1
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OS chart

by Paul Koning

Via one of the articles about that Unix V4 tape I found this https://eylenburg.github.io/os_familytree.htm which is quite an impressive chart of operating systems old and new. A few bits are clearly incorrect or missing; for example, P/OS and TRAX are both not there. I was going to mention them to the author of that chart but I don't actually know the correct placement. (Is P/OS an RSX-11/M or M+ derivative? I should know but don't.) Neat to see RSX-15 mentioned as the ancestor of RSX-11/D. Did the earlier RSX-11 versions ever ship? I know I have seen traces of /A and/or /C... The DOS-11 and RSTS entries aren't quite right either, I can send feedback for those. Also, while VMS is reasonably listed as RSX-11/M derivative, I always thought that VAXElan was unrelated. Along the same lines, where would MicroPower/Pascal fit? paul

6 months, 1 week

2
1
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compute gazette article summary

by Steve Lewis

As many have heard, COMPUTE!'s GAZETTE magazine has been resurrected as of this past July 2025. And its fifth issue for November is just days away. I'm not sure if attachments are working here, but there should be a catalog summary of the article titles (for those who aren't subscribed but were curious to browse the kinds of things being covered). That same summary catalog is also archived here: https://github.com/voidstar78/GC_TOC_SUM_CAT/blob/main/CG_2025_TSC_V0_1.TXT

6 months, 1 week

1
0
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Looking for a bootloader

by Peter Ekstrom

I am looking for the assembler listing for a bootloader for booting from MSCP disks like RD-disks. Google has not been very helpful and my assembler knowledge is not enough for me to write one from scratch. Does anyone have one they can share? - Peter

6 months, 2 weeks

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Friden edge punched cards

by Paul Koning

I was just looking at some Friden Flexowriter documentation, specifically the later 2300 series. They look somewhat more modern than the well known Flexowriters but seem to be comparable otherwise. I remember seeing a mix in the TU Eindhoven computer center, around 1970. The documentation mentions an optional feature, the ability to read and punch "edge punched cards". Those look like conventional Hollerith cards, but instead of the 12 row punching with rectangular holes, they are punched along the bottom edge in exactly the same manner as an 8 channel punched tape. In other words, imagine running a blank card through the tape path of a paper tape punch, and that's what you would see. I never ran into this before. Has anyone ever seen these in the wild? paul

6 months, 2 weeks

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Suggestions for Repairing a Keyboard Retaining Lug

by Rob Jarratt

I have an ANK 2462 keyboard for my Olivetti M24. The lugs on a couple of the retaining clips for the keyboard enclosure have broken off and disappeared. In fact, the keyboard came to me with tape holding it together! I guess I can live with using tape to hold it together, but it would be nice if I could fix this. I am looking for clever suggestions for how to replace the lugs. Any good ideas? The existing lugs look like this: https://1drv.ms/f/c/fc758a5a91b91301/Es7R00Lwr6lHosNt3JZlX20BXGTxi5N1SkYkl9K 0QAko3g?e=r1UnbI Thanks Rob

6 months, 2 weeks

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Author of tar for v7 Unix?

by Zane Healy

Does anyone happen to know who the author is of tar for v7 Unix? I have a friend who is trying to figure that out? Zane

6 months, 2 weeks

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Gimix hardware, MFM Hard Drive & 8" Double Side Drives

by Mike Katz

I just purchased an old Gimix computer (now if only I can get it from Orlando to Chicago before my friend goes down there for Christmas). It has an OMTI 20C-1 MFM hard disk controller with a IMI 5018 19MB hard disk drive in it. It has been recommended that i don't even turn the system on with the hard drive in it but rather I remove the drive an I send the IMI 18MB drive directly to a recovery house for data recovery. What do you all think about that? Do any of you have any experience with a recovery service for MFM ST-506 Drives? Also, does anyone have a half height 30MB or larger MFM ST-506 compatible drive that will work with the OMTI 20C controller for sale at a reasonable price. Preferably one that at least spins up. Also, does anyone have the syquest 5MB removable MFM drive and some cartridges, also at a reasonable price. My goal is to equip the Gimix with the following drives: * 2 80 Track DS/DD 5 1/4" half high floppy drives (in the system) * 2 77 Track DS/DD 8" Floppies (I have these in need of cleaning up, just not in a Gimix case) * 1 18 to 50MB MFM half high MFM Hard Drive (system has a full high 18MB drive) * 1 6MB Syquest removable cartridge drive half high (I need to find) At some point I would love to expand the RAM to as close to 1MB as I can (CPU/Motherboard supports up to 1016KB) and add a 3 or 4 port intelligent serial card and an intelligent parallel card (I'm sure these cards are unobtanium). Thank you all for your help If you have a dual 8" drive setup (double sided drives, and enclosure) that you need a good home for, please let me know. I'm in the Chicago Area. Thanks, Mike bitwiz(a)12bitsbest.com

6 months, 2 weeks

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Looking for my old MicroVAX-II

by Richard Cini

All – This is kind of a crazy request, but many years ago (20+ years), I gave away my MicroVAX-II to someone on the list. I can’t find any of the original emails, but I remember it was in a BA23 tower and included an external table-top drive enclosure with, I think, an RD54 in it. It ran Ultrix, but I can’t remember exactly which version. I’ve floated in-and-out of DEC over the years, and honestly, I’m kind of sorry I gave it away (like so many other systems I had over the years). I had gotten it in a haul from Temple University in the late-1990’s. Anyway, I’d love to get another one. So, if someone is looking to re-home a MicroVAX-II, keep me in mind. Thanks! Rich -- Rich Cini http://cini.classiccmp.org https://github.com/RichCini

6 months, 2 weeks

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Re: How hard would it be to make new dec tape media?

by Bob Vines

> > ---------- Forwarded message ---------- > From: Paul Koning <paulkoning(a)comcast.net> > To: "cctalk(a)classiccmp.org" <cctalk(a)classiccmp.org> > Cc: > Bcc: > Date: Sun, 2 Nov 2025 14:43:49 -0500 > Subject: [cctalk] Re: How hard would it be to make new dec tape media? > > > > On Nov 2, 2025, at 10:46 AM, Jon Elson via cctalk <cctalk(a)classiccmp.org> > wrote: > > > > On 11/1/25 20:49, ben via cctalk wrote: > >> How hard would it be to make new dec tape media? > >> 60 year tape could use a replacement. > >> Ben. > >> > > DecTape is laminated, ie. it has Mylar on both sides of the oxide. 50 > years ago, we made working replacements from 3/4" instrumentation tape, but > it was NOT laminated. It had a print-through issue where if left sitting > for a few months, it would start getting errors. I have no idea if there > is anywhere you can buy 3/4" instrumentation tape. Maybe you can get 3/4" > video tape. > > Bitsavers has the 3M spec for 480 and 481 sandwich tape, I'm not sure > which of these two is what DEC used. It seems crazy, but it can't hurt to > ask 3M if they still make that stuff. > > paul 10-20 years ago I had a good Point-of-Contact (POC) at 3M (before we both retired). I asked him whether they still (at that time) made DECtape media and was told that 3M had sold their magnetic media operations to another company who also got out of the business before I contacted them. I also asked my POC (and the contact at the other company) if any DECtape media had been kept in a warehouse or similar -- he checked 3M's inventory system and told me that they had no record of any remaining DECtape media. The other company's contact had a similar "you've struck out" story. Bob P.S. I thought that I read here or in a PDP-8-specific forum/mail-list that DECtape wasn't actually laminated on both sides, which apparently explained the visible red oxide material removed from dirty DECtapes while cleaning them (per whoever posted their observations)?

6 months, 2 weeks

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Re: Looking for an IF-20 interface for an Brother AX-45 typewriter. Saw this today. I was checking for other parts....

by Cliff Stage

I have one IF20 if you are interested.may work still, had allowed printing and disc storage for 2 × novels and and drafts. My only issue is probably the print head on the CE50 typewriter_ printer head needs replacement, but "modem" is ok I bet. Stagecliff(a)gmail.com

6 months, 2 weeks

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Is Ansgar Kückes on this list, or can someone put me in touch with him?

by bradmcook2013＠gmail.com

Hi all, Sorry to crash your party, but I'm doing research for a book and was hoping to connect with Ansgar Kückes, who owns this site about old school HP computers: https://www.hp9845.net/ Is he on this list? Or does someone know how to reach him? The contact methods on his site don't work anymore. Thanks. Brad

6 months, 2 weeks

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Unreliable Rotary Potentiometer

by Rob Jarratt

I have the contrast control on the monitor of my Olivetti M24 which has become unreliable, you only need to touch it and the display will disappear completely. It doesn't look too hard to replace the rotary potentiometer, but I was wondering if there is any way to "repair" it to keep the original part. It looks like this: https://1drv.ms/i/c/fc758a5a91b91301/ESPGlbvW5wxGpXPC5kXfzVMBTUUW96GThzDMqZ_ i8jq7tA?e=Ehmo1T Thanks Rob

6 months, 2 weeks

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reading DECtape

by Guy Fedorkow

We may have a half a dozen DECtapes, probably from the PDP-6 era, perhaps with ITS with content... Is there anyone, preferably in the MIT vicinity, who might have a working DECtape drive and be willing to try to read the tapes? Thanks /guy fedorkow

6 months, 2 weeks

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Re: reading DECtape

by Guy Fedorkow

Martin, Michael, Thank you! We don't have possession of the tapes yet, but, assuming that happens, I'll try RICM to see if their machines are working again. /guy fedorkow On 11/1/2025 1:00 PM, cctalk-request(a)classiccmp.org wrote: > Date: Fri, 31 Oct 2025 13:22:48 -0700 > From: Martin Eberhard<mfeberhard(a)gmail.com> > Subject: [cctalk] Re: reading DECtape > To:cctalk@classiccmp.org > Message-ID:<57DE7487-B3FA-4200-8D10-ACB4A5353CCE(a)gmail.com> > Content-Type: text/plain; charset=utf-8 > > If you don't find a closer alternative, I have working DECtape drives on my PDP8e (in California), as well as software that allows me to upload an entire tape image as a binary file (via Xmodem protocol). > > I'd be available to do this sometime after November 11. > > Martin > > Typing mangled by iPhone > >> On Oct 31, 2025, at 10:53 AM, Guy Fedorkow via cctalk<cctalk(a)classiccmp.org> wrote: >> >> We may have a half a dozen DECtapes, probably from the PDP-6 era, perhaps with ITS with content... >> Is there anyone, preferably in the MIT vicinity, who might have a working DECtape drive and be willing to try to read the tapes? >> >> Thanks >> /guy fedorkow >> >> >>

6 months, 3 weeks

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PDP-8 EAE

by Christian Corti

Can someone tell me the frequency of the R405 module in slot PF36 for the EAE of the classic PDP-8? Should it be the same as the R405 processor clock? Christian

6 months, 3 weeks

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"How to fix a Terak" tape?

by John Foust

I was reading my own Terak web page, and remembering that I'd read Doug Gale's history of computing at Cornell: https://ecommons.cornell.edu/bitstream/handle/1813/36810/00_TheEarlyYearsOf… and it mentions (at page 3.23) a "how to repair a Terak" video they made there, and he claims it was distributed to other universities that were also using Teraks. Has anyone ever seen this tape? - John

6 months, 3 weeks

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Re: MFM Hard Drive & 8" Double Side Drives

by David Gesswein

> From: Jim Davis <jim.p.davis(a)gmail.com> > Subject: [cctalk] Re: MFM Hard Drive & 8" Double Side Drives > Was anything MFM or RLL with a removible cart build in the 80's-90's? > I never heard of such a thing, Carts were scsi early 90's Syquest and > others?... > Yup https://en.wikipedia.org/wiki/SyQuest_Technology The early ones were ST412 type interface > From: Doc Shipley <doc(a)vaxen.net> > > Pretty sure Mr Gesswein is on this list but I don't see him post often. > Anyway, he designed a very handy MFM drive emulator: > > https://www.pdp8online.com/mfm/mfm.shtml > Yup but try not to hawk my board. When they say they want a drive I don't suggest alternatives. I also get the digest so most questions have been answered before I see them. Thanks all for the kind words.

6 months, 3 weeks

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The transistor invention

by Murray McCullough

I had forgotten that 75 years ago, Oct. 3, 1950, the transistor was invented leading to integrated circuits making possible personal computers and the interest of our love of computing. Where would we be without Bardeen's, Brattain's and Shockley's invention? Happy computing, Murray 🙂

6 months, 3 weeks

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Invention of the transistor

by Jeffrey Brace

> > > Message: 6 > Date: Fri, 24 Oct 2025 20:29:07 -0400 > From: Murray McCullough <c.murray.mccullough(a)gmail.com> > Subject: [cctalk] The transistor invention > > I had forgotten that 75 years ago, Oct. 3, 1950, the transistor was > invented leading to integrated circuits making possible personal computers > and the interest of our love of computing. Where would we be without > Bardeen's, Brattain's and Shockley's invention? > > Happy computing, > > Murray 🙂 > > Did you know the role of Camp Evans in the invention of the transistor? Find out here: https://youtu.be/6wFIVvb-5yQ

6 months, 4 weeks

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MFM Hard Drive & 8" Double Side Drives

by Mike Katz

I just purchased an old Gimix computer (now if only I can get it from Orlando to Chicago before my friend goes down there for Christmas). It has an OMTI 20C-1 MFM hard disk controller with a IMI 5018 19MB hard disk drive in it. I am thinking of trying to upgrade the hard drive. The Gimix System that I worked on had a half high 20MB drive and a Syquest removable 5MB drive. Does anyone have an old MFM drive laying around (half high or full height but larger than 18MB) and/or an MFM removable cartridge drive with cartridges? I am also going to try to rebuild a Vector Graphic Dual Store Dual 8" drive enclosure that I picked up at VCFMW. It suffered some dampness damage and I'm not sure the drives will come up. If you have a dual 8" drive setup (double sided drives, and enclosure) that you need a good home for, please let me know. I'm in the Chicago Area. Thanks, Mike bitwiz(a)12bitsbest.com

6 months, 4 weeks

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Rainbow H7842 PSU

by Robert Jarratt

I am trying to resolve a problem with a H7842 PSU from a DEC Rainbow. The AC OK output is not being asserted. I am looking at Tony Duell's schematic https://bitsavers.org/pdf/dec/rainbow/duell_schematics/psu.pdf and specifically at the Power OK circuit. I am using a test load of 1R on the 5V output and 6R on the 12V output, which is within the spec of the PSU. I see that under load the 5V output is only 4.4V, so I suppose it is to be expected that AC OK is not asserted. If I (briefly!) remove the load from just the 5V output, the 5V output is 5.27V, but the AC OK output is still not asserted. Using Tony's schematic, I looked at the input to the inductor on the secondary side (sheet marked "H7842 PSU Sheet 3") and it looks like this: https://rjarratt.wordpress.com/wp-content/uploads/2025/10/h7842-5v-secondar… I can't tell if that is correct or not. If I remove the 5V load the peaks narrow but are slightly higher. However, the puzzling thing is the 5V Pulse signal, it doesn't pulse, it is a steady 32V. I see that the 12V Pulse signal *does* pulse. The name would suggest it is supposed to pulse and its inputs do pulse as shown in the trace pictured above. I don't see how it is possible for 5V Pulse to be at a steady 32V, even if the diode or resistor that create the 5V Pulse signal was somehow bad. I guess this non-pulsing might be the problem, but I don't really know what to check here, I have lifted the diode and tested it, it seems fine. Does anyone have any suggestions please? Incidentally, for those who helped me with my Olivetti M24, I had already reassembled it and got this PSU out to look at next before receiving further suggestions on the M24. Once I have the H7842 sorted out I will go back to the M24 again. Thanks Rob

7 months

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EDUC8 FROM DOWN UNDER

by ben

http://www.sworld.com.au/steven/educ-8/ I would like to say google is your friend, but that is becoming more like your big brother from 1984.

7 months, 1 week

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VCF Swap Meet in Wall, NJ - Oct. 18

by Jeffrey Brace

The VCF swap meet is in three days. Are you ready? Click here for more information: https://vcfed.org/vcf-swap-meet/ Take care! Jeff Brace VCF Fundraising Manager

7 months, 1 week

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Emulator for the 1965 classic LINC

by Lars Brinkhoff

I have been working on this emulator, and it's now ready to use. https://github.com/open-simh/simh/pull/505

7 months, 1 week

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Old Dec/pdp11 manuals and software, is it archived?

by Christopher Zach

Going through my endless piles of *stuff* I have come across some manuals that might already be scanned, might not. So anyone know if these are archived somewhere? * TSX Plus: 4 RX02 floppies. Version 6.40, 6.5 o Along with release notes for 6.40 dated Jan 16, 1989 * SDC-RXV31 floppy controller manual: Sigma information systems, 1984 * DHV11 Technnical manual * DLV11 users guide ek-dlv11J-ug-001 * RA80 disk drive service manual (booklet, tough to scan) * RLV12 disk controller user's guide * MSC4806 Expansion memory board User's manual (10-29-1982) o MSC is Monilithis Systems Corporation o I think I have some of these boards * Computer Products: Instruction manual, Model 307 Clock Calendar * GTSC: Instruction manual, Model 304 Serial IO board * Fortran 11 reference manual (unsure of title) Thanks! Chris

7 months, 1 week

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vintage computing web sites

by Bill Degnan

I have updated the list I maintain of vintage computing resources. If there are any obviously-missing links contact me privately through vintagecomputer.net/contact.cfm https://www.vintagecomputer.net/browse_thread.cfm?id=147 NOTE: I deleted a few sites from the list, it's a shame some of them do not seem to have been backed up. Thanks Bill

7 months, 2 weeks

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Mini-exchange?

by Paul Koning

I was poking around eBay and up came a listing for a DEC "mini exchange", DFMSA. What is that? The name doesn't sound familiar. It looks like a box with a bunch of DB25 connectors on the back, but that doesn't help much. paul

7 months, 2 weeks

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Rescued a HP 2116B from being scrapped.

by Mattis Lind

A little while ago I was contacted by a person working for a big swedish company that asked if I was interested in saving a HP 2116B from being scrapped. On Monday I was able to pick up not just the HP 2116 but also some other HP21xx series machines that all were destined to be scrapped next week. When looking deeper into the HP 2116 I discovered that it was missing two non-optional boards. Without these boards the machine will not even power up. The boards missing are the power failure board ( 02116-6175 or 12588-6001) and the memory module decoder board ( 02116-6300 or 02116-6274 ). It is probably possible to create some kind of replacement boards but it would be really nice to have the original boards in such a nice machine. Is there anyone that has these boards that want to sell or trade them for something? /Mattis

7 months, 2 weeks

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HP 1611A logic state analyzer from the 80's in the 603 area code

by Bill Degnan

Anyone in the 603 area code interested in this (below)? I received an inquiry through kennettclassic.com but we don't need it. If interested contact me through kennettclassic.com/conatct.cfm or by private email. I don't know the person, but it looks like they want to sell, not donate. Bill "... *Hello, I have an old HP 1611A logic state analyzer from the 80's that was previously owned by Parker Brothers, no doubt used to test out chips for their electronic games and toys. I was wondering if you might know where I might be able to sell it or if you have any interest in it yourselves. It has all the documentation, including a leather bag intended to hold all the manuals. It powers on and still works. While I don't have any chips to test it with, I have seen it function and work with chips when I purchased it. *..."

7 months, 2 weeks

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Emulex SC03 disk capacity patch manual scanned

by Christopher Zach

Hi all! I noticed that while the Emulex SC03-B1 manual is on Bitsavers, the instructions for how to patch and use this board on a 22 bit Q Bus system are not. In the manual it says to "Write emulex". Fortunately I did 40 years ago and I have the "Emulex Disk Capacity Patches to DEC PDP-11 Operating Systems" manual which is now scanned and online at https://www.crystel.com/dec/sc03 Emulex document ID is PD9951002 Rev A, March 1983. Covers Rsx11M 3.2, 4.0, RSTS/E, and M+ versions at that time. Every page is scanned as a 300 DPI TIFF image, and there is a PDF version of the whole manual as well. Apparently they use the RH70 Unibus driver (which supports 22 bit without the unibus map) and then change a few bits to make it work on Q Bus. Enjoy and bitsavers owner please stick this in your archives as well. Chris

7 months, 2 weeks

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Re: vintage computing web sites

by donald donaldwhittemore.com

In the early 70s I worked at a place that had 2 S360/40s. On the 23rd floor of a 45+ year old building. At least 8 tape drives, 2 control units for them, 2 full banks of 2314, 2 1403 printers and 2 2540 card machines. I would assume updated wiring would have to have been run up 23 floors. When I started there was 1 S360/30. Don’t know if the normal building wiring would need to be updated for that.

7 months, 2 weeks

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Re: vintage computing web sites

by donald donaldwhittemore.com

I, for one, have fond memories of the S/360-20, 30 and 40. I ‘grew’ up running and programming those systems. FWIW, I have a punch card archive at www.ibmjunkman.com

7 months, 2 weeks

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HP9100B CRT

by hupfadekroua

Hi all, Are there any suggestions for the replacement of a HP9100B CRT? Best Andreas

7 months, 2 weeks

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Computer Data Systems "Versatile 2"

by Bill Degnan

Does anyone have, or has even seen, a Computer Data Systems "Versatile 2" s-100 computer from 1977? The company that produced it was from Newark, Delaware USA and I have been trying to track one down because I live nearby. Thanks Bill

7 months, 2 weeks

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Seattle Area: The "Interim Computer Festival" is tomorrow ...

by Michael Brutman

We're still waiting for VCF PNW 2020, but while we wait ... https://sdf.org/icf/ (This is a much smaller event than any VCF. It's also quite fun because it's not overwhelming.) -Mike

7 months, 2 weeks

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FSF

by Murray McCullough

The Free Software Foundation(FSF) is 40 this week. Central to the thesis of sharing software this organization has played and continues to play a seminal role. Though it's importance may be waning due to AI its reason to exist can't be overstated. Happy computing Murray 🙂

7 months, 3 weeks

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VCF Tech Swap Meet - Oct. 18 - Wall, NJ

by Jeffrey Brace

VCF Tech Swap Meet Oct. 18 in Wall, NJ INFO: https://vcfed.org/vcf-swap-meet/ VENDOR SINGUP: https://forms.gle/LpzDkF97THFNg3qg9 Jeff Brace VCF/MARCH Fundraising Manager Vintage Computer Federation is a 501c3 charity https://vcfed.org/ <http://www.vcfed.org/>

7 months, 3 weeks

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